Volume 47,Issue 2,2024 Table of Contents

1 Arc-plane failure mode and support design method of dual-element slope of soil and strongly weathered rock

LI Lianxiang , JIA Bin , ZHAO Zhongyang , HAN Zhixiao , LI Shengqun

2024, 47(2):1-13. DOI: 10.11835/j.issn.1000-582X.2021.057

[Abstract](217) [HTML](52) [PDF 1.78 M](984)

Abstract:
To investigate the non-destructive critical slope rate and stability assessment method for strongly weathered rock slopes with soil and highly weathered rock, based on Jinan's strata, suitable soil layer parameters for numerical simulation are determined. The strength reduction method is then applied to calculate the critical slope rate of the slope, providing reference for construction. The analytical solution for the slope's safety factor is obtained using the improved Swedish slice method and the slip line field method. These analytical solutions provide essential prerequisties for safety factor applications. Results show that strongly weathered rock experiences failure when the rock strata thickness exceeds half of the slope height or the slope ratio surpasses 1:0.5. The obtained safety factor from the analytical solution tends to be conservative, contributing to enhanced engineering safety. For soil and strongly weathered rock slope, the research findings help identify the failure area, facilitating the design of support schemes.

2 Experimental study on sea-sand ultra-high performance concrete

WEI Jiangang , CHEN Rong , HUANG Wei , BIAN Xuehai , MA Xiuxing

2024, 47(2):14-21. DOI: 10.11835/j.issn.1000-582X.2021.055

[Abstract](218) [HTML](86) [PDF 2.44 M](610)

Abstract:
In this paper, ultra-high performance concrete(UHPC) and ordinary concrete are prepared using undesalted sea-sand. The impact of sea-sand with varying chloride ion levels on the compressive strength, pore structure and durability of steel embedded in UHPC is investigated and compared with that of conventional concrete. The results show that the chloride ion content in sea-sand does not significantly negatively affect the compressive strength of UHPC. The critical pore radius of UHPC made with sea-sand is approximately 2 nm. Different from sea sand concrete, the porosity of sea-sand UHPC increases with the increase of chlorine content in sea-sand. Even when the chloride ion content in the sea sand is as high as 0.636%, the chloride ion permeability of the sea-sand UHPC remains negligible. The reinforcement in sea-sand UHPC is in a passive state and tends to stabilize after 28 days.

3 Corrosion prediction of reinforced concrete structure in marine atmospheres

ZHENG Shansuo , LIANG Zetian , YANG Song , MING Ming , HAN Chaowei

2024, 47(2):22-31. DOI: 10.11835/j.issn.1000-582X.2021.062

[Abstract](169) [HTML](54) [PDF 1.81 M](462)

Abstract:
Reinforcement corrosion is an important factor influencing the service life of reinforced concrete structures in offshore atmospheric environment. To study the effects of concrete carbonation and chloride corrosion on reinforcement corrosion in offshore atmospheres, an engineering measurement of reinforced concrete structures with varying ages was conducted. This assessment included measurements of compressive strength, carbonation depth of concrete, surface chloride concentration, and corrosion depth of steel. Utilizing the obtained measurements and prior research findings, a relationship model between concrete carbonation depth and compressive strength was developed. Additionally, a prediction model for reinforcement corrosion depth was established, taking into account both concrete carbonation depth and the surface chloride concentration of reinforcement. Building upon these models, a damage plastic analysis of reinforced concrete frame columns with different ages and axial compression ratios was performed using Abaqus analysis software, revealing the seismic performance variation of corroded reinforced concrete frame columns concerning service age and axial compression ratio.

4 Fuzzy reasoning algorithm and its application with three types of negation

WU Xiaogang

2024, 47(2):32-39. DOI: 10.11835/j.issn.1000-582X.2020.066

[Abstract](171) [HTML](54) [PDF 597.98 K](458)

Abstract:
In fuzzy reasoning, both the compositional rule of inference (CRI) and the similarity-based approximate reasoning (SAR) methods are built on classical fuzzy sets with only one negation. With considering the characteristics of the generalized fuzzy set(GFScom) that possesses three types of negation (contradiction, opposite and medium negation), an extension is made to the implication operator of the CRI fuzzy reasoning method. The definition and formula of GFScom closeness degree, which incorporates three types of negation, are presented. A new computational method of fuzzy approximate reasoning, named GSAR(generalized similarity-based approximate reasoning), is proposed. The method is proven to have reducibility for fuzzy modus ponens (FMP). Through comparative examples, the new GSAR fuzzy reasoning method not only overcomes the subjectivity and arbitrariness of the CRI method in establishing fuzzy relation matrices, but also objectively and effectively reflects three types of negative information in fuzzy reasoning, thereby enriching the forms of fuzzy reasoning.

5 Automatic identification of rock structure surface based on digital borehole images

ZHANG Zhanxyu , SU Junhui , LYU Guangzu , LUO Weibin , XU Cunlu

2024, 47(2):40-50. DOI: 10.11835/j.issn.1000.582X.2024.02.005

[Abstract](221) [HTML](48) [PDF 3.78 M](563)

Abstract:
Digital borehole camera technology can accurately acquire information regarding the structural surface characteristics of rock within a borehole. To address the shortcomings such as labor-intensity, subjectivity, and computational intensity associated with existing digital borehole image analysis, this paper introduces a new analysis scheme to automate the recognition of borehole interior images captured by digital borehole camera technology. The proposed scheme begins by uniformly illuminating images using a two-dimensional gamma function light-adaptive correction algorithm. Next, edge features are extracted using a pre-trained DexiNed network. To tackle edge point noise and extract the region of interest, the Epremoval method is employed. Finally, the method performs polynomial fitting on the characterization data in the image utilizing the Taylor expansion of the sine curve. The parameters of the rock structure surface are obtained by calculation, spatial transformation and mathematical transformation of the obtained curves. The algorithm is applied to the digital borehole image of a tunnel project as an illustrative example. The obtained results are compared with the results of manual assisted interpretation, revealing superior recognition capabilities of the proposed method.

6 Pun detection basd on pseudo-label and transfer learning

JIANG Siyu , ZHANG Zhiheng , JIANG Libiao , MA Le , CHEN Boyuan , WANG Lianxi , ZHAO Liang

2024, 47(2):51-61. DOI: 10.11835/j.issn.1000.582X.2024.02.006

[Abstract](215) [HTML](76) [PDF 1.26 M](465)

Abstract:
To address the problem of shortage of the pun samples, this paper proposes a pun recognition model based on pseudo-label speech-focused context (pun detection based on pseudo-label and transfer learning). Firstly, the model uses contextual semantics, phoneme vector and attention mechanism to generate pseudo-labels. Then, it combines transfer learning and confidence to select useful pseudo-labels. Finally, the pseudo-label data and real data are used for network theory and training, and the pseudo-label labeling and mixed training procedures are repeated. To a certain extent, the problem of small sample size and difficulty in obtaining puns has been solved. By this model, we carry out pun detection experiments on both the SemEval 2017 shared task 7 dataset and the Pun of the Day dataset. The results show that the performance of this model is better than that of the existing mainstream pun recognition methods.

7 Research on the security enhancement for power information systems based on quantum security

PENG Fei , TIAN Zengyao , ZHANG Xiaohua , AN Tianyu , MENG Qingdong , CHEN Zhikui

2024, 47(2):62-74. DOI: 10.11835/j.issn.1000.582X.2021.152

[Abstract](152) [HTML](43) [PDF 2.00 M](511)

Abstract:
Power systems are fundamental to state development, and measuring the security of the power information system is crucial. In existing power information systems, most security methods rely on encryption algorithms like RSA algorithm, which face growing threats from the increasing computing power of the Internet and quantum computers. With recognizing the urgent need for information security in power systems and the unconditional security offered by quantum communication, this paper explores the application of quantum security communication in power information systems. Specifically, through a detailed analysis of the procedure and security factors of the standard SSL protocol, this paper proposes a security enhancement method that is compatible with existing Internet protocol foundations. The proposed method enhances the source of random numbers by incorporating preset quantum random numbers, based on either a quantum random number generator or a quantum key distribution network. Implemented on the OPENSSL VPN evaluation platform, experiments show that the proposed security enhancement method can improve the security level of power information systems without significantly increasing system complexity or cost.

8 Lightweight privacy protection scheme for cloud audit

ZHANG Xiaoqin , YAO Yuan , WANG Ying

2024, 47(2):75-83. DOI: 10.11835/j.issn.1000.582X.2024.02.008

[Abstract](167) [HTML](46) [PDF 895.89 K](388)

Abstract:
In the context of the explosive growth of big data, the emergence of cloud storage services has significantly facilitated user data storage. The on-demand nature of cloud servers further contributes to their widespread popularity. However, this convenience comes at the expense of direct user control over data stored in the cloud, exposing it to potential damage from various uncertain factors. This brings great challenges to the advancement of cloud storage. To address these challenges, a data auditing scheme is proposed, emphasizing lightweight calculation and verification. This solution streamlines the user’s label calculation operation before uploading data, ensuring data security during the upload process. This approach concurrently reduces the calculation tasks of both the cloud server and the auditor, minimizing overall calculation overhead. To protect user data privacy, the scheme incorporates scrambling encryption inspired by image encryption. This enables users to use random functions to scramble the data block’s location, while still allowing the auditor to calculate the actual data block location for successful auditing. The results show that the proposed solution effectively saves computing resources for users, servers, and auditors during the audit process, thereby improving overall process efficiency.

9 A method for measuring the tensile elastic modulus of cross-ply composite plates based on S₀ Lamb waves

WANG Yunlin , LIU Yaolu , HU Ning

2024, 47(2):84-94. DOI: 10.11835/j.issn.1000-582X.2023.257

[Abstract](179) [HTML](86) [PDF 2.92 M](563)

Abstract:
This paper introduces a method for measuring the elastic modulus of cross-ply composite plates based on Lamb waves. Cross-ply composite plates are equivalent to a single-layer orthotropic plate with 9 independent elastic constants. The sensitivity of the group velocity of S₀ Lamb waves to elastic constants is studied. It is observed that the group velocity of S₀ Lamb waves is only related to the tensile elastic modulus and the in-plane Poisson’s ratio of the orthotropic plate at the low-dispersive frequency-thickness products range. By analyzing the change ranges of equivalent engineering elastic constants for cross-ply composite plates, it is discovered that the change in the in-plane Poisson's ratio of cross-ply composite plates is small enough to ignore its effect on the group velocity of S₀ Lamb waves. Therefore, the group velocity of S₀ Lamb waves can be used to estimate the tensile elastic modulus of the cross-ply composite plates, and a mapping relationship between the group velocity of S₀ Lamb waves and the tensile elastic modulus can be established. The method has been verified by numerical simulation and experiment, and the error between the tensile modulus and the actual value of the composite plate obtained by this method is less than 10%. This provides convenience for the measurement of relevant structural parameters in aerospace and other industrial fields.

10 FFT acceleration algorithm for contact problems based on triangular element discretization

CHEN Nan , ZHU Kai , JIANG Zhizhen , GONG Shiyu , LI Pu , JIN Xiaoqing

2024, 47(2):95-105. DOI: 10.11835/j.issn.1000-582X.2023.258

[Abstract](149) [HTML](34) [PDF 1.83 M](470)

Abstract:
Effectively solving the governing equations for contact problems often involves complex mathematical theory, while the distribution of contact stress is highly random in practical engineering applications. This study proposes a novel algorithm based on the triangular load discrete element and the discrete convolution fast Fourier transform (DC-FFT) algorithm. This algorithm provides a high-precision and reliable method for efficiently solving the contact response of a solid under any load distribution. Compared to the commonly used uniform load element discrete method, the analytical solution of the triangular element is more complex. However, it better simulates the characteristics of contact load distribution, accounting for situations where the load at the contact edge increases from zero or decreases to zero. The stress component under the action of the triangular and uniform load elements is derived based on the “excitation-response” characteristics of the contact influence coefficient matrix. This information is used to optimize the solution method of the triangular load discrete element. By constructing the stress solution in the form of a discrete convolution, including the influence coefficient matrix, the stress superposition effect of a target node under the action of all elements can be further simplified and accelerated by using the DC-FFT algorithm for highly repetitive matrix calculations. Programming and calculation analysis show that the proposed algorithm based on the triangular load element is accurate and efficient.

11 Study on chaotic characteristics of heterogeneous physical double pendulum

KONG Linghui , LIU Dingyang , JIAN Kailin

2024, 47(2):106-118. DOI: 10.11835/j.issn.1000-582X.2023.255

[Abstract](168) [HTML](64) [PDF 3.35 M](514)

Abstract:
To address the impact of materials with uneven mass distribution on the motion of double pendulum systems in engineering practice, a heterogeneous double pendulum model was established based on the homogeneous physical double pendulum model. This model incorporated variables, such as the position of the center of mass and the moment of inertia of the pendulum. To further explore the chaotic characteristics of the system, the heterogeneous double pendulum system was approximated from a Hamilton system to a quasi-Hamilton system. The dynamics equation of the double pendulum system was obtained using the Euler-Lagrange equation of the second kind. The energy threshold for Smale horseshoe chaos in the quasi-Hamiltonian system was determined using Melnikov method with two degrees of freedom, serving as the chaos condition for the Hamiltonian system. Through programming in Matlab, the correctness of the chaos condition was verified using numerical methods such as maximum Lyapunov exponential diagram, bifurcation diagram and Poincare section diagram. The influence of each parameter on the system’s motion state and action mechanism was analyzed in detail. The results show that the chaos threshold of heterogeneous double pendulums depends on various factors, including the initial energy of the double pendulums, the position of the center of mass of the first pendulums and the ratio of the moment of inertia of the two pendulums. With different values for each parameter, the system changes from a regular motion state with a chaos threshold to an irregular and complex motion state without a chaos threshold. The reasons for the system alternating between chaotic and quasi-periodic states were explained, and theoretical predictions were validated. The differences between the theoretical threshold and actual numerical simulation results were explained when the center of mass of the first pendulum, the mass ratio of the two pendulums, and the ratio of moment of inertia of the two pendulums were set to their limit values. On this basis, the relationship between parameter values and the applicability of Melnikov method were further explored, and the parameters under which Melnikov method was no longer applicable were discussed by numerical simulation classification.

12 Dynamic characteristics of the mechanical antenna based on vibrating permanent magnet

ZHANG Miao , WANG Jishuo , NING Huiming , HUANG Kaiyan , YUAN Weifeng

2024, 47(2):119-132. DOI: 10.11835/j.issn.1000-582X.2023.254

[Abstract](152) [HTML](47) [PDF 2.88 M](538)

Abstract:
In the traditional field of wireless communication, the application of long-wave communication is constrained on small and medium-sized platforms due to the requirement of large sized signal-transmitting antennas. This paper proposes and develops a three-degree-of-freedom cut-out beam structure of the vibration permanent magnet type mechanical antenna prototype based on the inverse piezoelectric effect, vibration theory, and Maxwell’s equations. It establishes an electric-mechanical-electromagnetic energy theory model and investigates the radiation influencing factors of the mechanical antenna along with its frequency modulation technique. The experimental results validate that electromagnetic wave signals can be frequency-modulated by exciting different vibration modes of the mechanical antenna prototype. This research offers novel theoretical and technical perspectives for low-band signal communication.

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