• Low complexity MED algorithm based on numerical analysis theories

  YANG Xi, TIAN Chong, FANG Ruyi, LIU Zeyu, ZHANG Yinhang, LEI Kejun

  Available online:May 19, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022353

  Abstract(4436) HTML(0) PDF(1.21 M)( 17417)

  Abstract:The classical maximum eigenvalue detection (MED) algorithm has excellent performance in detecting correlated signals. However, with the increasing signal dimensionality, the MED algorithm faces serious problems in the calculation efficiency and implementation of test statistic and decision threshold, thus greatly limiting the further application of the algorithm in modern cognitive communication systems. To this end, a low-implementation complexity MED algorithm based on a numerical analysis theoretical framework is proposed. The new algorithm uses the Rayleigh quotient accelerated power method to iteratively compute the test statistic, which has a fast convergence rate in detecting high-dimensional signals compared with the classical power method; meanwhile, different from the classical look-up table method, a threshold calculation method based on the cubic spline interpolation method is proposed, which can quickly determine the decision threshold corresponding to any given target false-alarm probability. The proposed MED algorithm effectively improves the computational efficiency and reduces the complexity of algorithm implementation while maintaining the detection performance of the original algorithm, which is particularly attractive for spectrum sensing problems in high-dimensional conditions. Finally, the simulation results demonstrate the effectiveness of the proposed algorithm.

• Design of Terahertz Fundamental Up-conversion Mixer with Good Port-to-Port Isolation

  Meng Fanyi, Liu Hao

  Available online:May 19, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022355

  Abstract(1431) HTML(0) PDF(3.07 M)( 15210)

  Abstract:A terahertz fundamental up-conversion mixer with a high local oscillator (LO)/ radio frequency (RF) and local oscillator / intermediate frequency (IF) port isolation was presented, which was in the IHP 0.13μm SiGe BiCMOS process. The mixer adopted Gilbert’s double-balanced structure, local oscillator signal was transmitted through the Coplanar Waveguide (CPW) to suppress the transmission asymmetry caused by the strong parasitic coupling effect in the transmission process, which reduced the characteristic of LO/RF port isolation deterioration caused by the asymmetry. By adopting an asymmetric switch interconnection structure, the imbalance of the parasitic coupling of the local oscillator signal at the collectors of the switching transistors was reduced, and the cancellation efficiency of the local oscillator signal at the collectors of the switching transistors was improved. And the local oscillator signal was suppressed at the port of intermediate frequency by arranging the position of the transconductance transistors in a reasonable layout. The post-simulation results show that under the power supply voltage of 2.2V, the local oscillator signal is 230GHz and the intermediate frequency signal is 2-12GHz, when the up-conversion mixer works at 218-228GHz, the LO/RF port isolation is greater than 24dB, LO/IF port isolation is greater than 20dB, the conversion gain is -4dB to-3.4dB. The output 1dB compression point is -14.8dBm with an intermediate frequency signal is 10GHz. The DC power consumption is 42.4mW, the core area of the chip is 0.079mm2.

• Performance Analysis of RIS-assisted Hybrid RF-FSO Transmission Systems

  YUAN Yongjie, YANG Liang, CHEN Shenghai, MA Rongchang

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022296

  Abstract(1230) HTML(0) PDF(965.81 K)( 15227)

  Abstract:Free space optical (FSO) communications offer high speed, low cost, and strong anti-interference ability. However, the atmospheric turbulence-induced fading causes deterioration in the performance of FSO communication systems. The conventional solution is to use RF links as parallel communication links to improve the system performance. On the other hand, reconfigurable intelligent surfaces (RIS) can be employed to further improve the received signal-to-noise ratio of the RF link due to its advantages of low loss, easy deployment, and no complex coding and decoding. In this paper, an RIS-assisted hybrid RF-FSO transmission system is proposed to improve the communication quality of service. Based on this hybrid model, exact expressions for the outage probability, average BER, and channel capacity are derived, and Monte-Carlo simulations are presented to verify the accuracy of the analytical results. Results show that the performance of the proposed system is significantly improved compared to the conventional hybrid RF-FSO system.

• Research on scattering characteristic of PT?symmetric beam based on piezoelectric shunting technology

  Wang Gang, Luo Caiming

  Available online:May 17, 2022  DOI:

  Abstract(1017) HTML(0) PDF(1.51 M)( 14922)

  Abstract:The mechanism for asymmetric transmission is an important issue for enhanced sensing, amplification and asymmetric control of elastic waves. Parity-Time symmetric systems may provide a simple solution. The concept of Parity-Time symmetric systems comes from quantum mechanics, and one of its characteristics is unidirectional reflectionlessness. A PT symmetric beam for flexural waves is designed, which is based on piezoelectric shunting technology. Firstly, the PT symmetric condition is derived. Then, based on the effective medium method and finite element simulation, it is verified that the effective parameters of gain and loss unit meet the PT symmetric condition. The tunability of exception points is studied by changing the resonant frequency and the shunting resistance. Finally, the scattering property of the PT sym-metric beam is derived by transfer matrix method and finite element simulation, and the relationship between exceptional points and unidirectional non-reflection is illustrated. The calculated and simulated results show that the PT symmetric beam has several exceptional points including 511Hz and 520.5Hz. When the incident flexural waves of 511Hz is applied at the right side of the PT symmetric beam, the reflection coefficient is close to zero. However, when the frequency of the incident flexural waves changes to 520.5Hz, it should be applied on the left side of the PT symmetric beam in order to gain a total transmission without reflecting. The structure of the proposed PT symmetric beam is simple and the exceptional points of it are tunable, which can be used to achieve better asymmetric transmission of flexural wave.

• Research on Online Community Knowledge Sharing Scheme Based on Blockchain

  XIE Renqiang

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022297

  Abstract(1052) HTML(0) PDF(842.54 K)( 14724)

  Abstract:With the rapid development of Internet, virtual communities are emerging. While providing innovative resources, these communities also have problems such as low willingness of users to share and lack of good incentive mechanism. Blockchain can better solve these problems and promote community knowledge sharing. This paper constructs an online community knowledge sharing scheme based on Multi Chain, puts forward the resource access and storage mode of "metadata cloud storage" and designs the metadata information table in detail, designs the overall framework of the knowledge sharing scheme and the key processes of some businesses, puts forward the consensus mechanism of "Nominated Proof of Stake (NPOS) to design the blockchain network, Some functions of online community knowledge sharing are realized. Through analysis and experiment, the scheme of this paper has good scientific rationality, safety and execution efficiency, and has good reference value for the development of other related projects.

• T-shaped image dehazing network based on wavelet transform and attention mechanism

  YangYan, WuXuDong, DuKang

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022299

  Abstract(1146) HTML(0) PDF(1.42 M)( 14955)

  Abstract:Affected by suspended particles such as haze in the atmosphere,images taken outdoors often suffer from low contrast and low visibility. Existing dehazing methods fail to make full use of the local feature information of the image, and cannot fully extract the global details of the image. Therefore, there are problems such as incomplete dehazing and loss of image details. For this reason, this paper proposes a T-shaped image dehazing network based on wavelet transform and attention mechanism. Specifically, the proposed network obtains the edge detail features of the hazy image by performing multiple discrete wavelet decomposition and reconstruction on the image, and proposes a feature attention module that takes into account both the global feature and the local information extraction of the image, which strengthens the network"s learning in image visual perception and detail texture. Secondly, in the process of feature extraction, a T-shaped method is proposed to obtain multi-scale image features, which expands the network"s representation ability. Finally, perform color balance on the reconstructed clear image to obtain the final restored image. A large number of experimental results in synthetic data sets and real data sets show that the network proposed in this paper has superior performance compared with other existing network models.

• State-sensitive-based Event-triggered H∞ Control for Path Tracking of Unmanned Ground Vehicle

  sun hong tao

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022300

  Abstract(741) HTML(0) PDF(1.29 M)( 14732)

  Abstract:This paper proposes a state-sensitive event-triggered H∞ control strategy to solve the problem of unmanned ground vehicle (UGV) path tracking control under communication restriction. Firstly, the corresponding path tracking control model is established according to the dynamics of the connected vehicle. Secondly, a novel state-sensitive event-triggered communication (SS-ETC) strategy according to the state perception of path tracking in real time is proposed. Then, an event-triggered H∞ controller is designed by combining with time delay system modeling method and Lyapunov stability theory. The proposed dynamic event-triggered communication strategy based on state perception can dynamically adjust the communication threshold according to the state measurements of the control system, and effectively realize the adaptive co-design of UGV communication and control. Finally, the effectiveness of the proposed dynamic event-triggered control strategy is verified by simulation experiments.

• Implementation of Improved Sorted QR Decomposition on FPGA

  Chen jian, Zhuang yao yu, Yang dan, Zhang jun jie

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022351

  Abstract(843) HTML(0) PDF(1.16 M)( 14761)

  Abstract:Although MIMO technology can improve the utilization rate of spectrum, multi-dimensional signal processing brings great challenges to the detection of MIMO signals. Based on the analysis of various MIMO detection algorithms, QR decomposition is selected as the research object, which is a kind of nonlinear algorithm. In order to obtain higher performance of detection, the sorted QR decomposition is further studied and propose the sorting scheme based on L1-norm. Using Matlab for performance simulation, the L1-norm sorting strategy and the L2-nrom sorting strategy have basically the same impact on MIMO system, but the L1-norm sorting strategy reduces the computational complexity. On this basis, the hardware structure of improved sorted QR decomposition by Givens rotation on FPGA is proposed. Comparing with the solution of L2-norm, the L1-norm strategy reduces at least 29.2% combinational logic resources and 32.4% register resources when calculating a single column norm in the realization of 4×4 channel matrix decomposition. Comparing with similar designs, the frequency of operating clock has been significantly improved.

• A lightweight key sharing protocol for IoT devices based on PUF

  wangzhenyu, Guo Yang, Li Shaoqing, Zeng Jianping

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022352

  Abstract(949) HTML(0) PDF(1.02 M)( 14791)

  Abstract:With the development and application of communication networks, the Internet of Things carries the safe transmission and storage of a large amount of sensitive information. Since devices are usually small in size and resource-constrained, complex security primitives are not suitable for authentication of lightweight IoT devices. This paper proposes a lightweight anonymous key shared authentication protocol for IoT devices, which generates a shared key by the physical unclonable function(PUF) and uses security primitives such as the MASK algorithm and the Hash function. The security analysis and verification are accomplished by Ban logic and ProVerif to prove that the protocol ensures security attributes such as anonymity, non-repudiation, and forward/backward confidentiality. Compared with other protocols, this protocol has the characteristics of low computing cost, small communication overhead and storage capacity, and high security performance, which is suitable for the secure communication transmission of resource-constrained devices.

• Underwater multi-object segmentation technology based on spectral clustering with multi-feature weighting

  LIU Guangyu, CAO Yu, ZENG Zhiyong, ZHAO Enming, XING Chuanxi

  Available online:May 17, 2022  DOI: 10.16339/j.cnki.hdxbzkb.2022354

  Abstract(1206) HTML(0) PDF(1.60 M)( 14771)

  Abstract:Sonar image is seriously polluted by noise, which leads to the problem of low precision in underwater multi-target segmentation.Therefore, an underwater multi-object segmentation technique based on self-adjusting spectrum clustering combined with entropy weight method is proposed.The technology first by self-tuning spectral clustering of sonar image pixel clustering processing, make the image is divided into multiple independent area, and then according to the characteristics of complementarity and more sections of the redundancy of the statistical information entropy characteristics, brightness, contrast, long and narrow degree, entropy weight method is used to analyse the characteristics more empowerment and the optimal selection of a target area,Then the optimal target region is matched with all regions by multi-feature similarity. Finally, all target regions are segmented automatically by adaptive threshold iterative method according to the matching results of similarity. Experimental results show that there is not over-segmented of noise interference regions, and target regions segmented have higher accuracy, which verifies the effectiveness of the proposed method.

Vol, 52, No.5, 2025    

• Investigation on Seismic Performance of a Novel Prefabricated Steel Inner Core-UHPC Composite Hollow Column

  SHAO Xudong1，2，ZHAO Xiangru1，2，WU Suiwen1，2?，SHAO Zongxuan3，He Guang1，2

  2025,52(5):1-16, DOI:

  Abstract(5) HTML(1) PDF(92.30 M)( 2)

  Abstract:In this paper， a novel prefabricated steel inner core-UHPC composite hollow column with a pocket connection is proposed for a novel super long-span steel-UHPC arch bridge to accommodate the span length， accelerate the construction， and reduce the self-weight and cost. The column consists of a steel inner hollow section and an exterior UHPC shell. The steel inner core can serve as the formwork of the column and provide an additional energy dissipation source. The design concept of the column and the connection details are first presented， followed by a detailed experimental program. To be specific， a 2/5-scale column was designed based on the preliminary design of the novel arch bridge and tested under the most unfavorable axial load ratio （0.24） in a pseudo-static manner to investigate the seismic performance of the proposed column， including the damage pattern， the connection performance at the interface of the prefabricated column， displacement ductility， energy dissipation capacity， stiffness degradation， residual deformation， curvature distribution and strains of the steel inner core. The test results showed that the proposed column failed in a flexural manner， including the yielding of the steel inner core and reinforced bars and crushing of the UHPC shell in the plastic hinge region； the joint remained intact and no visible crack was observed at the interface between precast and post-cast UHPC， indicating the proposed column with the pocket connection is reliable. In addition， the tested column had large equivalent damping ratios but low displacement ductility， mainly due to the mismatch between the thickness of the steel core plate and the thickness of the UHPC thin wall layer. The large axial load ratio （0.24） could be another potential cause. Moreover， the experimental results were used to validate a numerical model， on which a parameter study was performed on the novel column from the prototype bridge. The results show that the increase in the axial load ratio will result in a reduction in the ductility ratio. When the axial ratio varies between 0.05 and 0.2， the ductility coefficient of the prototype column is generally close to or larger than 3.0. The research results can provide the basis for the subsequent design and application of steel inner core-UHPC columns.

• Three-dimensional Simulation of Large Deformation Failure for Slope Reinforced with Anti-slide Piles Based on Material Point Method

  MA Xiangyu1，WANG Huaan2，LU Meng1?，ZHOU Mingliang1，ZHANG Jie1

  2025,52(5):17-27, DOI:

  Abstract(3) HTML(1) PDF(22.53 M)( 1)

  Abstract:Current studies on the three-dimensional （3D） large deformation analysis of slopes with reinforcement structures remain limited. In this study， a 3D numerical model for a slope reinforced with anti-slide piles is constructed using the material point method. The failure modes of the slope with anti-slide piles are analyzed， and the effects of the pile length， location， and spacing on slope failure are also discussed. The results show that， when the anti-slide piles are located at the slope toe， the soil above the anti-slide piles is prone to local failure， inducing overtopping and sliding. Increasing the pile length reduces the area of the plastic zone， but exacerbates shallow sliding and increases runout. When the anti-slide piles are located in the middle of the slope， the displacement of the slope after failure is the smallest， and the reinforcement effect is the best； however， when the pile length is roughly the same as the depth of the potential slip surface， the presence of piles may lead to a longer runout distance after failure. The increase of the pile spacing causes the plastic flow of the soil between the piles. When the anti-slide piles are located at the slope crest， the soil beneath them is easily dislodged and slides and the reinforcement effect is poor.

• Springback Prediction and Compensation of Multi-camber Aluminum Alloy Gusset Joint Plates Using Response Surface Method

  GUO Xiaonong1?，LI Gen1，ZENG Qiang2，TRIVANA Vanda3

  2025,52(5):28-40, DOI:

  Abstract(2) HTML(0) PDF(70.88 M)( 0)

  Abstract:In free-form aluminum alloy single-layer latticed shells， the members rely on the gusset joints to connect. To meet these assembly requirement of the gusset joint， the joint plates need to be stamped into complex shapes with multiple cambers. However， the springback phenomenon reduces the forming accuracy and may cause difficulty in joint assembly. To improve the forming accuracy of the joint plates， it is crucial to predict and compensate for the springback. Firstly， forming experiments were conducted on 6 joint plate specimens， the residual cambers were scanned with a 3D scanner， and the springback values were calculated. Secondly， a mixed algorithm of explicit dynamic and implicit static algorithm was used for the simulation of the springback process on the joint plates. Compared with the experiment springback values， the simulated values only had a mean relative error of 4.31%. Subsequently， response surface models for springback prediction were constructed based on 1 500 numerical simulation results， and the coefficient of determination of the model was 0.988， indicating a high accuracy. Finally， based on the springback prediction response surface model， a springback compensation method for multi-camber aluminum alloy gusset joint plates was proposed and validated with 20 numerical examples. The method was used to design 20 groups of joint plates with different geometric parameters and camber combinations. The results show that the method can effectively compensate the springback of the plates.

• Experimental Study on Flexural Performance of Prefabricated UHPC Composite Beams with Different Interface Shear Connections

  FANG Zhi1，2?，LU Rui1，HONG Jinsheng1，HE Dehua3，WANG Xiaohuang3， CHEN Jianning3，HUANG Jiajun1

  2025,52(5):41-56, DOI:

  Abstract(2) HTML(0) PDF(63.67 M)( 0)

  Abstract:Ultra-high performance concrete （UHPC） composite beams， formed by the UHPC precast beams and precast bridge slabs through cluster shear connectors， have a wide range of applications in prefabricated structures. Four-point bending tests were conducted on three prefabricated UHPC composite beams with different degrees of shear connection （0.47， 0.94 and 1.41 respectively） and one UHPC cast-in-place beam for clarifying the flexural performance of prefabricated UHPC composite beams. The results show that the shear connection degree has a significant impact on the flexural performance of prefabricated UHPC composite beams. For the composite beams with shear connection degrees of 0.47 and 0.94， diagonal cracks appeared on the web of the prefabricated beams below the edge pocket due to the large shear force caused by the shear keys， which finally led to the failure of the shear keys. The flexural capacities of the prefabricated UHPC composite beams with shear connection degrees of 0.47， 0.94 and 1.41 were 76%， 97% and 100% of that of the cast-in-place beam， respectively. The ductility coefficients for these beams were 28%， 38% and 37% of that of the cast-in-place beam. Additionally， their elastic stiffness before cracking was 52%， 72% and 85% of that of the cast-in-place beam， respectively. A calculation method for the flexural capacity of prefabricated UHPC composite beams with different shear connection degrees was provided， and its applicability was verified through experimental results.

• A Carbon Emission Prediction Model for Highway Tunnel Construction Based on Improved Stacking Multiple Model Integration

  WU Jiarun1，LIN Yuliang1，3?，XING Hao2，NING Xi2

  2025,52(5):57-65, DOI:

  Abstract(5) HTML(0) PDF(4.46 M)( 2)

  Abstract:Tunnel engineering， as a significant component of transportation infrastructure， has increasingly received attention for its carbon emissions during the construction process. It is a significant scientific basis for controlling carbon emissions and achieving carbon reduction in tunnel design by establishing a rational model for predicting carbon emissions in tunnel construction. Accordingly， the dataset concludes a total of 120 samples of tunnel construction carbon emissions （per meter） with different lining designs based on the construction of the Menglü highway tunnel project， considering 12 characteristic parameters， including the surrounding rock level， the total length of the tunnel， and so on. Based on the traditional Stacking algorithm， this study proposes an improved Stacking algorithm of multi-model fusion to predict carbon emissions in tunnel construction. The improved Stacking algorithm combines the various base learner training models with the residual weighting approach， which is obtained through cross-validation. Besides， the improved Stacking algorithm utilizes the original training set and the prediction results of the combined base learner as the meta-learner inputs. Therefore， the improved Stacking algorithm is not only less sensitive to noise， but also retains the original dataset information. The results demonstrate that the improved Stacking algorithm is superior to three single base learners as well as the traditional Stacking algorithm in terms of root mean square error （ERMSE）， mean absolute error （EMAE）， and determination coefficient （R2）. Consequently， it recommends the improved Stacking algorithm for predicting carbon emissions in tunnel construction.

• Study on Out-of-plane Mechanic Performance of Single-sided Stainless Steel Double Steel Plate Composite Shear Wall for Nuclear Facilities

  WU Lili1?，WANG Xingge1，WU Haipeng1，YANG Yuxuan1，YU Yue2

  2025,52(5):66-78, DOI:

  Abstract(2) HTML(0) PDF(49.00 M)( 1)

  Abstract:The reactor pool of nuclear power stations adopts a single-sided stainless steel double-steel plate composite shear wall. To study the out-of-plane mechanic performance of this type of composite shear wall， two 1∶2.5 scaled specimens with different bolt and tie bar configurations were designed. Low-cycle reciprocating load tests were conducted to investigate the failure mode， hysteretic behavior， stiffness degradation， energy dissipation， as well as the impact of bolt and tie bar reduction on the out-of-plane performance of the single-sided stainless steel double steel plate shear wall. The test results showed that during loading， the common steel plate first buckled， followed by the buckling of the stainless steel plate， and the side sealing steel plate weld cracked. Subsequently， multiple bolts and reinforcing tie bars broke， leading to the crushing of concrete until the specimen failed. The hysteresis curves of the two specimens were full， indicating good seismic performance， and the plastic development of common low-alloy steel plates was sufficient. When the bolt spacing increased from 80 mm to 90 mm， the average ductility coefficient of the specimens decreased by 8.3%， and the bearing capacity in both positive and negative out-of-plane directions decreased by less than 10%. A finite element model of the single-sided stainless steel double steel plate shear wall was established using Abaqus software， and it was compared with experimental results， showing good agreement between them. The finite element model was further used to analyze the impact of parameters such as concrete strength， steel content ratio， and the difference in tensile bearing capacity between the two sides of the steel plates on the out-of-plane bearing performance of the wall. The results indicate that the strength of the concrete has a minor impact on the bearing capacity of the shear wall. When the unilateral steel content ratio of the specimen increases from 0.5% to 2.5%， the bearing capacity of the low alloy steel plate in the tensile direction rises by 160%， and that of the stainless steel plate increases by 176%. When the difference in tensile bearing capacity of the steel plates on both sides exceeds 30%， the difference in bearing capacity of the shear walls in both directions exceeds 15%. Based on the experiments， recommended values for each parameter are provided.

• Experimental Study on Bearing Capacity of Precast Piles with Enlarged Pile Toes and Pile Side Synchronous Grouting

  WANG Kuihua1，GENG Shaohan1，XU Yinghao1，WU Juntao1?，QIU Shangyin1，HUANG Shan2，3

  2025,52(5):79-87, DOI:

  Abstract(3) HTML(0) PDF(18.33 M)( 11)

  Abstract:To meet society’s increasing demand for low-cost and high-strength pile foundations， this paper proposes a new type of pile， a precast pile foundation with enlarged pile toes and synchronous grouting on the side of piles. The new pile type has the advantages of low energy consumption and high efficiency. On the one hand， it has easy construction steps and conventional construction equipment， which is convenient for engineering popularization and application. On the other hand， enlarged pile toes increase the effective diameter of the piles and thus improve the bearing capacity of pile end. Meanwhile， the cement slurry infiltrates into the surrounding soil， which can improve the characteristics of the pile soil contact surface， thereby increasing the pile side friction. To further prove the load-bearing characteristics of the synchronously grouted precast pile foundation with enlarged plie toes， an indoor model test is carried out in this paper. The test results show that the bearing capacity of the synchronous grouting model pile with enlarged pile toe is higher than that of the conventional pile with equal cross-section when the pile top is compressed， and its bearing capacity is further improved due to the existence of cement slurry on the pile side. The test results reveal the bearing mechanism of the new pile type and show the superiority of the new pile type’s bearing capacity. The results of this research can provide theoretical support for new pile-type engineering practices.

• Experimental Study on Buffeting Force Spanwise Correlation of Bluff Double-side Box Girders

  LI Yu?，FENG Pu，CHEN Zhe，LI Jiawu

  2025,52(5):88-98, DOI:

  Abstract(1) HTML(0) PDF(48.11 M)( 0)

  Abstract:A Π-shaped girder is the most commonly used in medium-span cable-stayed bridges. However， there are few studies on the buffeting force spanwise correlation of Π-shaped girders. To improve the accuracy of the buffeting calculation of Π-shaped girders， research was conducted on the buffeting force spanwise correlation. In this study， the section models of bluff double-side box girders （BDSBG） with three aspect ratios （B/H=5， 10 and 15） were made. Then， in the two grid turbulent flow fields and the signature turbulence caused by uniform airflow， the pressure-measured tests were performed to measure the wind pressure time-history of each pressure tap， which was used to calculate the buffeting forces and their power spectra， spanwise cross-correlation coefficients， and spanwise coherence functions. Moreover， the effects of B/H and flow fields on the power spectrum and spanwise correlation of the buffeting forces of BDSBG were studied. The results show that： 1） with the increase of B/H， the energy of the buffeting forces gradually decreases； the higher the turbulence intensity of the flow field， the more energy is provided to the buffeting forces； moreover， the influence of the vortex shedding frequency on the buffeting force power spectrum can be greatly weakened by the grid turbulent flow-field. 2） with the increase of B/H， both the spanwise correlation and coherence of the buffeting forces increase； these values are much greater than those of the fluctuating wind， and the difference in the spanwise correlation and coherence between the buffeting forces and the fluctuating wind also increases with the increase of B/H； furthermore， with the increase of the turbulence intensity， the buffeting force spanwise correlation increases， while both the discreteness of the buffeting force spanwise coherence and the influence of the vortex shedding frequency on the buffeting force spanwise coherence decreases.

• Comparative Test Study on Interfacial Shear Resistance of Different Joints of Prefabricated Diaphragm Walls

  LIU Xiaodong1，2，MU Baogang1?，HUANG Liji2，LIU Minghu2，DENG Huiyuan2，GONG Weiming1，ZHAO Jia1，XIAO Shiwei3

  2025,52(5):99-107, DOI:

  Abstract(2) HTML(0) PDF(73.47 M)( 12)

  Abstract:With the rapid development of building industrialization， prefabricated diaphragm walls have been increasingly applied in underground engineering. However， existing research on the shear resistance of different types of vertical joints remains inadequate. This study designed four model components incorporating rigid and flexible joints and conducted direct shear loading tests and analysis. The test results showed that under the same conditions， rigid joints generally had higher shear-bearing capacity than flexible joints， among which the steel pipe tie joint has the highest load-bearing capacity and the socket-type joint has the lowest； all four types of joints failed due to brittle shear failure modes. During failure， the anchorage structure of rigid joints affected the crack morphology with vertical cracks along the steel pipe wall in rigid joints. However， the flexible joints exhibited cracks crossing the joint section. Strain test data further verified the development characteristics of cracks under shear conditions. Meanwhile， it is found that the PCI formula provides a relatively accurate calculation of the shear-bearing capacity for rigid joints. The above research lays a foundation for the promotion and application of prefabricated diaphragm walls.

• Study on Performance of New Cement-soil Mixing Pile Cementitious Material Curing Foundation Soil

  CHEN Ruiyun1?，SHENG Min1，HU Jie1，XU Tao1，WANG Yating1，DONG Wenling2，ZHOU Fen2

  2025,52(5):108-117, DOI:

  Abstract(4) HTML(0) PDF(17.14 M)( 1)

  Abstract:This study investigated the mechanical properties of foundation soil solidified with geopolymer binder materials， replacing traditional cement in cement-soil mixing piles. The experiment used sodium silicate to activate montmorillonite， slag fly ash， and carbide slag to form a geopolymer binder for soil solidification. The unconfined compressive strength of the solidified foundation soil was tested for various proportions， along with strength variations of two groups of specimens after immersion in HCl solution （pH=5） and 5% Na?SO? solution for 7， 14 and 28 days. X-ray diffraction （XRD） and scanning electron microscope （SEM） were used for composition and microstructure analysis. The results indicated that， compared to using slag alone， the addition of a small amount of fly ash enhanced the compressive strength of geopolymer-solidified soil. Incorporating 5% montmorillonite participated in the geopolymer reaction， adsorbed moisture， and filled pores， thereby increasing the strength of the geopolymer-solidified soil. However， excessive montmorillonite content adversely affected the mixture due to its water-absorbing and expanding properties. Using a sodium silicate modulus of 0.8， with a dosage of 12%， 5% montmorillonite， and a slag-to-fly ash ratio of 9∶1， the geopolymer-solidified soil achieved a compressive strength of 3.44 MPa after 28 days of standard curing. After 28 days of immersion in HCl solution， the strength was decreased by 26.2%， and after 28 days in NA2SO4 solution， it was decreased by 17.4%. The compressive strength of the geopolymer-solidified soil was 2.73 times that of cement-solidified soil， demonstrating excellent resistance to acid and sulfate attack.

• Experimental Study on Uniaxial Tensile Properties of High-strength and High-ductility Concrete

  DENG Mingke，WANG Yitong，YANG Jiasheng?，ZHANG Yangxi

  2025,52(5):118-127, DOI:

  Abstract(3) HTML(0) PDF(25.62 M)( 1)

  Abstract:To investigate the uniaxial tensile properties of high-strength and high-ductility concrete， （HSHDC）， 12 groups of specimens were designed， and uniaxial tensile tests were carried out. The effects of water-binder ratio （0.14， 0.16 and 0.18）， PE fiber volume ratio （1.5%， 2.0% and 2.5%）， fiber types （PE and PVA）， and PE fiber diameters （22 μm， 35 μm and 40 μm） on the uniaxial tensile behavior of thin sheets were studied. The influence of the above factors on the energy absorption capacity of HSHDC was analyzed in terms of the strain energy density before the peak stress. The results show that with the increase of the water-binder ratio， the tensile strength of HSHDC increases first and then decreases， while the ultimate tensile strain increases. The tensile strength of HSHDC increases with the fiber volume ratio， while the ultimate tensile strain of HSHDC decreases with the increase of fiber volume ratio when the water-binder ratio is low， but not vice versa when the water-binder ratio is large. When the water-binder ratio of 0.16 and 0.18 occurs， the strain energy density of HSHDC before the peak is higher with different fiber volume ratios. Compared with the HSHDC specimen mixed with PVA fiber， the HSHDC mixed with PE fiber has better tensile properties and energy absorption capacity， and the PE fiber with a small diameter is more suitable for HSHDC preparation. Finally， the dense matrix of HSHDC and the rough surface of PE fiber were studied by scanning electron microscope （SEM）.

• Research on Impact Test of Precast Concrete Beam with Pressed Steel Sleeve Connections

  CHEN Qingjun1，2，LI Yunlong2，WANG Yingtao3?，YAO Miaojin2，HE Zhanchao2，CAI Jian1，2

  2025,52(5):128-140, DOI:

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  Abstract:To investigate the behavior of precast concrete （PC） beams with pressed steel sleeves under impact loads， a total of 6 beams with pressed steel sleeves connection of 3 different assembly types， and 2 cast-in-place reinforced concrete （RC） beams were tested under free-falling drop-weights， while 4 corresponding beams were tested under static load. The assembly form included mid-span splice， end splice， and composite beam forms. The research focused on the effects of different hammer masses and impact velocities on the dynamic responses of the precast concrete beams under the same impact energy， including failure modes， mid-span deflection， impact force， and deformation energy. The results obtained are as follows： the failure modes and crack development of RC and PC beams with different splicing types are basically consistent， but the cracks in mid span splicing beams are more concentrated at the splicing part， and the overlapping of splicing sections and impact positions is more unfavorable to the structure. The pressed steel sleeve is reliable as the assembly and connection form of precast concrete beams. When the impact energy of 6 762 J remains unchanged， the increase of impact mass from 230 kg to 400 kg has little effect on the peak impact force. But the average impact force has increased， and the increase in amplitude of the three types of splicing PC beams exceeds 25%. The maximum deformation energy consumption of PC beams with different splicing types is equivalent to that of RC beams， with a ratio of input energy ranging from 50% to 70%. Except for the mid-joint precast beam， increasing the impact mass at the constant energy increased the maximum deformation energy consumption of the test beam more than 15%.

• Research on Effective Reinforcement Depth of Dynamic Compaction of Stone-filled Embankment Considering Deformation and Stress Response

  XU Ping1，3，HOU Weiqi1，QIAO Shifan2?，DONG Hui1，3，LUO Zhengdong1，3

  2025,52(5):141-153, DOI:

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  Abstract:Taking the dynamic compaction reinforcement project of the super large particle size high stoned-filled embankment of Pan-Xing highway of Guizhou province as an example， the effective reinforcement depth of high stoned-filled embankment was comprehensively studied based on the variation law of embankment compacted fill density with depth after dynamic compaction and the attenuation characteristics of tamping energy propagation of dynamic compaction. Meanwhile， a calculation formula for effective reinforcement depth of dynamic compaction was derived based on the volumetric strain equation considering the crater depth and compacted fill density control requirements. A field compaction test was carried out to obtain the functional relationship between the compacted fill density and static soil pressure increment under the compaction energy. Additionally， a field dynamic compaction test was carried out to analyze the variation laws of embankment surface displacement and the change of dynamic and static stress inside the embankment with the tamping times. The results indicate a strong correlation between the compacted fill density and static soil pressure increment under the compaction energy. The crater depth reached 932 mm， and the maximum embankment surface uplift near the crater reached 50 mm after eight tamping times. The peak value of dynamic stress and the static soil pressure increment in the depths of the embankment decreases rapidly with the depth， and the embankment surface uplift near the crater decreases more sharply with the increase of distance from the edge of the crater. The vertical effective reinforcement depth and horizontal effective reinforcement radius of dynamic compaction are about 5.0 m and 2.5 m， respectively. The modified coefficient of the established calculation formula for effective reinforcement depth of dynamic compaction was fitted based on the measured data of effective reinforcement depth under different tamping times. Furthermore， the effective reinforcement depth optimization formula considering the horizontal and vertical action effects of dynamic compaction and the reinforcement quality control requirements was established.

• Research on Ridership Share of Urban Rail Transit with the Beta Random Effects Regression Model

  LIU Chenhui1，2，3，4?，SU Meiling1，WANG Xingyu1，ZHANG Mingyu1，WU Qi1，ZHANG Jiawei1

  2025,52(5):154-161, DOI:

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  Abstract:To identity the key factors affecting ridership share of urban rail transit（URT）， with the panel data of 14 cities from 2010 to 2021， the share of the URT ridership in the total public transit ridership is analyzed here to identify the key influencing factors. Considering the possible heterogeneities over city and year， a Beta regression model with city-level and yearly random effects is built to identify the key influencing factors from conventional bus， URT， and socio-economic aspects. The model is estimated with the integrated nested Laplace approximation method. The estimation results show that the number of conventional buses per 10 000 people， the URT length per 10 000 people， and the URT connectivity have significantly positive effects on the URT ridership share， while the length of bus routes per 10 000 people， GDP per capita， and road area per capita are insignificant. Besides， both city and year show significant random effects： the URT ridership shares are found to vary differently across cities， but they generally show an increasing trend during the survey period.

• Effect of Nano Calcium Carbonate on Static and Dynamic Splitting Tensile Properties of Polyvinyl Alcohol Fiber Reinforced Concrete

  KANG Yumei?，LI Yuelan，GAO Xue，HUANG Wei

  2025,52(5):162-171, DOI:

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  Abstract:Polyvinyl alcohol （PVA） fiber can inhibit the crack propagation of concrete， but the inhibition effect is limited to the micro-cracks inside the matrix and has few effects on nano-scale cracks. The impact of nano-CaCO3 on the static and dynamic splitting tensile properties of PVA fiber reinforced concrete was studied in this paper， and the strengthening mechanism was analyzed by scanning electron microscope （SEM） test. The results show that the static and dynamic splitting tensile properties of PVA fiber reinforced concrete are significantly improved when the content of nano-CaCO3 is 1.5%. When the curing time is 28 d， the content of nano-CaCO3 is 1.5% and the content of PVA fiber is 0.6%， compared with the same content of PVA fiber reinforced concrete without nano-CaCO3， the static splitting tensile strength is increased by 8.6%， and the dynamic splitting tensile strength and dissipation energy at 2.25~3.08 s-1 strain rate are increased by 11.2% and 12.4%， respectively. SEM image analysis shows that the addition of nano-CaCO3 can promote the formation of hydration products to fill the bonding interface between PVA fiber and matrix and the pores and micro-cracks inside the cement matrix， enhance the bonding degree between fiber and matrix and the crack resistance of PVA fiber， thus improving the static and dynamic splitting tensile properties of concrete materials.

• Research on IFC Framework of Ming and Qing Historic Timber Building

  WANG Ru1，2，WANG Yao1?，HUANG Wei1，2，HU Youwen1，ZHANG Xiaofeng1

  2025,52(5):172-184, DOI:

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  Abstract:Research on multi-dimensional collection methods for historic building heritage information has become increasingly comprehensive. However， the interaction among various types of heritage information suffers from inconsistent content and format， which hinders effective utilization. This article focuses on historic timber buildings from the Ming and Qing dynasties， presenting a systematic approach for establishing an industry foundation classes （IFC） framework. Through analysis， heritage information during the protection process is categorized into five core dimensions： architectural， historic， artistic， degradation， and restoration. Based on the CIDOC conceptual reference model （CRM）， knowledge graphs for Ming and Qing historic timber buildings were created for each dimension heritage information. Additionally， the corresponding elements of heritage information expression were integrated and aligned with the IFC architecture framework， ultimately leading to the establishment of the IFC expression framework for Ming and Qing historic timber buildings. By systematically organizing the IFC heritage information of Ming and Qing history timber buildings， standardized solutions are provided for the construction of the IFC framework of history buildings. This approach promotes the efficient sharing and application of historic building heritage information.

• Experimental Study on Low Temperature Crystallization of Rubber Material for Isolation Bearing Based on DSC

  DU Yongfeng1，2，WANG Guanghuan1?，LI Yuan1，ZHANG Chao1

  2025,52(5):185-194, DOI:

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  Abstract:To analyze the deterioration mechanism of rubber isolation bearings at low temperatures， the low temperature crystallization properties of rubber materials used for isolation bearings in China under no-strain conditions were investigated. Differential scanning calorimetry （DSC） was used to investigate the glass transition temperature and isothermal crystallization melting of natural vulcanized rubber used for the production of isolation bearings by two typical enterprises in China. The results show that the crystallinity of the isolation bearing increases with the extension of the holding time at low temperatures without strain. Additionally， the crystallization properties of different vulcanized natural rubbers are different due to various factors such as origin， growing environment， and vulcanization process. Only when the ambient temperature is below -60 ℃ the rubber isolation bearings produced by the materials used in this study lose their practical engineering value. In the actual service process， the isolation bearing is affected by the dual factors of low temperature and strain. The research results in this paper provide a reference and basis for revealing the deterioration mechanism of the mechanical properties of the isolation bearing at low temperatures and enhance our understanding of the mechanical behavior of the rubber isolation bearing at low temperatures.

• Wind Load Characteristics of Super High-rise Buildings with Rounded Arc Edge Section under Different Wind Directions

  LIU Qingkuan1，2，3?，YANG Shuochen1，ZHENG Yunfei4，YANG Xiongwei5，WANG Qiansen1

  2025,52(5):195-208, DOI:

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  Abstract:In practical engineering， super high-rise buildings with the combination of fillet treatment and arc convex edge of the building plan are quite commom. A study on the wind load of this kind of structure was conducted. Based on the wind pressure time history data obtained from the wind tunnel pressure test， the wind pressure distribution， aerodynamic coefficient， and aerodynamic power spectrum of super high-rise buildings with different arc edge bulge rates were analyzed. The influence of the convex rate of the section arc edge on the wind load characteristics of the super high-rise building under different working conditions was obtained. The research shows that in the range of measured wind direction angle， with the increase of arc edge bulge rate， for the wind pressure distribution on the building surface， the average wind pressure coefficient of the leeward side CD and the crosswind side AD is closer to the straight edge model as a whole. The changes of windward surface AB and crosswind surface BC are more complicated. For the mean， fluctuating， and extreme wind pressures， the straight edge model is smaller than the arc edge model， and the arc edge leads to the maximum increase of extreme wind suction by 42%. For the across-wind force coefficient and its power spectrum， the fluctuating lift coefficient and the fluctuating base bending moment coefficient have an increasing trend as a whole， and the peak value of the power spectrum changes irregularly. For the downwind force coefficient and its power spectrum， the average drag coefficient and the average base bending moment coefficient gradually decrease， and the power spectrum has no obvious spectral peak. The downwind force is mainly affected by the incoming flow. The arc edge treatment of the corner square building section may lead to excessive local wind pressure， which has an adverse effect on the wind resistance design of the curtain wall but is beneficial for reducing the downwind wind force of the structure. By analyzing the wind load characteristics of the building surface， a reference can be provided for the aerodynamic shape selection and wind resistance design of such buildings.

• A Position Detection Method of Prestressed Ducts Based on 3D Laser Scanning and Deep Learning

  ZHU Jiongyi1，WANG Yi1，JIANG Haili2，LIU Panpan2，WANG Dejiang1?，DU Xiaoqing1

  2025,52(5):209-218, DOI:

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  Abstract:The position of prestressed ducts has a significant impact on the bearing capacity of prestressed concrete members. A position detection method for ducts based on 3D laser scanning and deep learning is proposed to improve the efficiency and accuracy of ducts position detection. Firstly， a dataset containing prestressed ducts is produced by the 3D laser scanning method. Then， the ducts point cloud is obtained by an efficient large-scale 3D point cloud semantic segmentation network （RandLA-Net）. The centroid of the ducts point cloud slice is obtained by using the bracket box midpoint method and circle fitting constraints method. Finally， the centerline of the ducts is fitted by the back-propagation neural network （BP network）. The detection results of actual prestressed concrete box girder duct position using this method show that even under the interference of complex surrounding environments such as box girder reinforcing steel skeleton and construction tire frame， this method can obtain the complete prestressed duct position. The maximum detection error is less than ±10 mm， which meets the requirements of relevant construction specifications.