Hasil untuk "Engineering geology. Rock mechanics. Soil mechanics. Underground construction"

NIU Tingting1, 2 , HUO Mingying1, SUN Xin3, ZHANG Zhichao4

Geogrid is one of the main factors affecting the load distribution of pile and soil in piled embankments, but the related research is not in-depth enough, especially under dynamic train load. For this reason, a piled embankment model with a similar ratio of 1:5 is established, the dynamic deformation characteristics of the geogrids are studied by using M-shaped wave of the actuator outputting to simulate the dynamic load of the train, and the interaction mechanism among the dynamic load of the train, geogrids, gravel, and piles is revealed. The results show that the geogrid dynamic strain time history curves under the middle and the shoulder of the embankment present a "positive M" shape, and the geogrid dynamic strain time history curves at the slope show an "inverted M" shape. The geogrid-gravel cushion behaves as a "semi rigid platform" in the initial stage of vibration, and acts as a "tensioned membrane" after a period of vibration. When the train runs at high speed, the cumulative strain under the middle and the shoulder of the embankment increases monotonically with the increase of the loading amplitude. At the foot of the side slope, the cumulative strain of the geogrid gradually decreases with the increase of the loading amplitude.

Wenzheng Li, Hua Jiang, Xiaodong Fu et al.

Based on the drilling, logging and field analysis, this paper discusses the lithofacies paleogeography of the Ordovician and its petroleum potential in the Middle-Upper Yangtze Area, South China. Results show that Ordovician of the Middle-Upper Yangtze Region can be divided into Tongzi Formation, Honghuayuan Formation, Meitan Formation, Shizipu Formation, Pagoda Formation, Linxiang Formation and Wufeng Formation from bottom to top. During the Early Ordovician Tongzi Period and Honghuayuan Period (Tremadocian Stage), a carbonate rimmed platform developed in the study area with lots of grain shoals in Guangyuan-Weiyuan Areas and Lichuan-Tongzi Areas of Southeastern Sichuan Basin. To the Meitan Period (Floian and Dapingian and Early Darriwilian Stage), a mixed carbonate platform with clastic sedimentary rock deposition developed in study area. In Middle-late Ordovician Shizipu and Linxiang-Pagoda Period (Late Darriwilian and Hirnantian-Sandbian Stage), a carbonate ramp developed in Middle-Upper Yangtze Region. At the end of the Ordovician (Hirnantian Stage), Wufeng Formation deposited in a retention basin due to the restriction of peripheral uplift and paleo-land. Two sets of reservoir-source assemblages developed in the Ordovician, with three sets of source rocks developed in the study area. First, the lower Cambrian Qiongzhusi Formation acted as the main source rock, and the hydrocarbon migrated upward to the Ordovician reservoir along the fault. Second, the Wufeng-Longmaxi Formation acted as source rock, and hydrocarbon migrated to the Lower Ordovician along the karst crust and the fault. Third, the Lower Ordovician Meitan-Shizipu Formation acted as source rock, hydrocarbon can migrate upward to the upper Ordovician reservoir directly, which deserves exploration attention.

ZHANG Zhiwei 1 , ZHENG Gang 1, CHENG Xuesong 1 , LIANG Rongzhu 2, YANG Haibin 3, ZHAO Jing 3, ZHONG Zhiwu 3

The longitudinal axial force and the yield of joint bolts can result in significant nonlinear variations in the rotational stiffness of circumferential joints of shield tunnels subjected to external loading. The existing computational methods related to longitudinal deformation of tunnels often simplify the tunnels as an equivalent continuous long beam with the constant bending stiffness, which are challenging to reflect the nonlinear rotational effects of circumferential joints. Firstly, taking the transverse performance and elastic-plastic behaviors of bolts of a shield tunnel into account, the expressions for the rotational stiffness of joints under weak tensile bending, pure bending and compressive bending conditions are derived based on the strict elliptic parametric equation for cross-section of tunnels, respectively. Secondly, the shield tunnel is modeled as a series of Timoshenko short beams connected by nonlinear rotational springs and linear shear springs along its longitudinal direction, meanwhile the soil-tunnel interaction is simulated using the normal and tangential Winkler foundation springs, which are evenly distributed on the outer wall of the tunnel. Then, the state space method is used to obtain the longitudinal discontinuous displacement of the shield tunnel under external loads, and the iterative solution process associated with its longitudinal deformation under axial pressure is proposed. Finally, the proposed method is validated by comparing the existing theoretical methods and measurements associated with the upper excavation-induced longitudinal deformation of the tunnel, and the parametric analyses are also carried out to explore the impacts of longitudinal axial force and transverse performance on surface surcharge-induced longitudinal deformation of the tunnel using an engineering case. The results show that the yield of longitudinal bolts can significantly increase the joint opening and tensile area between adjacent rings. The application of axial pressure can prominently reduce the longitudinal displacement, joint opening and shearing dislocation of the shield tunnel induced by the upper excavation. The parametric analyses show that as the longitudinal axial force increases from tension to compression, the maximum longitudinal displacement and rotational angle of the tunnel decrease nonlinearly, and the decrease rate at first increases and then decreases, while the maximum joint opening diminishes approximately linearly. The reduction of lateral stiffness of the tunnel can lead to significant growth in its longitudinal displacement and joint opening, as well as a slight diminution in the shearing dislocation.

Dipin Khati, Yijin Liu, David N. Palacio et al.

Applications of Large Language Models (LLMs) are rapidly growing in industry and academia for various software engineering (SE) tasks. As these models become more integral to critical processes, ensuring their reliability and trustworthiness becomes essential. Consequently, the concept of trust in these systems is becoming increasingly critical. Well-calibrated trust is important, as excessive trust can lead to security vulnerabilities, and risks, while insufficient trust can hinder innovation. However, the landscape of trust-related concepts in LLMs in SE is relatively unclear, with concepts such as trust, distrust, and trustworthiness lacking clear conceptualizations in the SE community. To bring clarity to the current research status and identify opportunities for future work, we conducted a comprehensive review of $88$ papers: a systematic literature review of $18$ papers focused on LLMs in SE, complemented by an analysis of 70 papers from broader trust literature. Additionally, we conducted a survey study with 25 domain experts to gain insights into practitioners' understanding of trust and identify gaps between existing literature and developers' perceptions. The result of our analysis serves as a roadmap that covers trust-related concepts in LLMs in SE and highlights areas for future exploration.

Noah M. MacKay

In Ref. arXiv:2502.08816, Hawking radiation was analyzed through a statistical mechanics framework, revealing a structured microstate description of black hole horizons and information transfer into the radiation background. This study extends that approach by formulating Hawking radiation and black hole evaporation in the language of stochastic mechanics, employing an analytical Langevin framework and a numerical Euler iteration scheme. Both methods confirm that small black holes behave as thermal systems with Gaussian noise, while larger black holes develop a structured noise spectrum that aligns with the gradual contraction of the horizon. This suggests an alternative interpretation of Hawking radiation as an effective surface fuzziness, encoding horizon-scale fluctuations. The appendix provides a Wolfram Mathematica blueprint for numerical simulations, open to heuristic modifications for further exploration of black hole noise spectra.

Jan Tobochnik, Harvey Gould, William Klein

An agent-based model of the economy is generalized to incorporate investment and guaranteed income mechanisms in addition to the exchange and distribution mechanisms considered in earlier models. We find realistic wealth distributions and realistic values of the Gini coefficients and the Pareto index. We also show that although the system reaches a steady state, the system is not in thermal equilibrium. The nonequilibrium behavior is associated with the multiplicative noise generated by the investment mechanism.

Xiaofei DUAN, Fengxin KANG, Xiaohua WU et al.

Objective In order to accomplish the objective of sustainable development and utilization of geothermal energy, it is imperative to elucidate the optimal production-reinjection well spacing considering varying quantities and temperatures of reinjection. Methods The thermal reservoir of the Guantao Formation in northern Shandong Province is selected as the research subject, and a conceptual model and mathematical model for layered thermal reservoir development are established. COMSOL Multiphysics multifield coupling simulation software is employed to develop a geothermal production-reinjection well spacing calculator. The accuracy of the model is validated through parameter fitting and simulation results. Results Based on the software APP development function, which is guided by the input of ordinary users, the relevant parameter input was simplified for ease of use, leading to the establishment of an application for calculating geothermal production-reinjection well spacing. In contrast to previous studies that solely focused on production-reinjection well spacing, this study calculates optimal spacings under various conditions to meet real-world operational needs. The results indicate that the optimal production-reinjection well spacings, without experiencing thermal breakthrough are 290, 330, 360 m and 390 m at flow rates of 40, 60, 80 and 100 m3/h respectively. Conclusion In the layered conductive sandstone thermal reservoir area of northern Shandong, a reliable geothermal production-reinjection well-spacing calculator was developed through simplification of the conceptual model and credible numerical simulation results. Hydrothermal numerical simulation serves as a robust approach to determine rational production-reinjection well spacings, which are crucial parameters for geothermal development and utilization projects including exploitation quantity, recharge quantity, injection temperature, and production-reinjection well spacing. These determinations contribute to the sustainable development and utilization of geothermal resources.

Zizheng Guo, Bixia Tian, Yuhang Zhu et al.

The aim of this study is to investigate the impacts of the sampling strategy of landslide and non-landslide on the performance of landslide susceptibility assessment (LSA). The study area is the Feiyun catchment in Wenzhou City, Southeast China. Two types of landslides samples, combined with seven non-landslide sampling strategies, resulted in a total of 14 scenarios. The corresponding landslide susceptibility map (LSM) for each scenario was generated using the random forest model. The receiver operating characteristic (ROC) curve and statistical indicators were calculated and used to assess the impact of the dataset sampling strategy. The results showed that higher accuracies were achieved when using the landslide core as positive samples, combined with non-landslide sampling from the very low zone or buffer zone. The results reveal the influence of landslide and non-landslide sampling strategies on the accuracy of LSA, which provides a reference for subsequent researchers aiming to obtain a more reasonable LSM.

Sumio Watanabe

Mathematical equivalence between statistical mechanics and machine learning theory has been known since the 20th century, and research based on this equivalence has provided novel methodologies in both theoretical physics and statistical learning theory. It is well known that algebraic approaches in statistical mechanics such as operator algebra enable us to analyze phase transition phenomena mathematically. In this paper, we review and prospect algebraic research in machine learning theory for theoretical physicists who are interested in artificial intelligence. If a learning machine has a hierarchical structure or latent variables, then the random Hamiltonian cannot be expressed by any quadratic perturbation because it has singularities. To study an equilibrium state defined by such a singular random Hamiltonian, algebraic approaches are necessary to derive the asymptotic form of the free energy and the generalization error. We also introduce the most recent advance: the theoretical foundation for the alignment of artificial intelligence is now being constructed based on algebraic learning theory. This paper is devoted to the memory of Professor Huzihiro Araki who is a pioneering founder of algebraic research in both statistical mechanics and quantum field theory.

GAN Lei, JIN Hongjie, SHEN Zhenzhong, , XU LEI, MA Hongying

The influences of the roughness of fracture surface and the loading-unloading environment on seepage characteristics of fracture cannot be ignored. To study the influences of the fracture surface with different joint roughness coefficients (JRC) and loading-unloading of confining and osmotic pressures on the seepage evolution laws of rough single fracture of limestone, five groups of limestone samples with a single fracture with different JRCs are prepared. The self-developed seepage test system for the fractured rock mass is used to conduct a seepage test of the fractured samples with different JRCs under loading-unloading of confining and osmotic pressures. The results show that the seepage flow and permeability of different fractured samples decrease with the increase of the confining pressure, and the permeability of each sample has a power function relationship with the confining pressure, with the minimum R2 of 0.9583. There is an obvious hysteretic effect during the unloading of the confining pressure. The JRC has a great influence on the hysteretic degree during unloading, which is logarithmic with the decline and recovery. During the process of loading-unloading of pressure, the change of seepage flow through the single fracture is positively correlated with the osmotic pressure, while the permeability decreases continuously. There is a good correlation between the decreased value of seepage flow through the single fracture and the JRC after a cycle of loading-unloading of pressure. A prediction model for seepage flow of fracture after loading-unloading of osmotic pressure is proposed.

LU Dechun 1, JIN Chenyi 1, LIANG Jingyu 2, LI Zehua 1, DU Xiuli 1

The mechanic characteristics of sand have obvious features of state dependence, which is mainly reflected by the fact that the deformation characteristics of sand in different stress and density states significantly differ. The reasonable description for the state-dependent hardening rule and dilatancy rule of sand is the basis to describe the state-dependent deformation characteristics of sand. A differential expression which can effectively describe the isotropic compression and critical state of sand is proposed. Based on the hardening rule under isotropic compression condition, a state-dependent hardening factor ω is proposed, and the state-dependent hardening parameter H is developed in order to reasonably decide the magnitude of plastic strain increment. In the process of determining the direction of plastic strain increment by adopting the non-orthogonal plastic flow rule, the influences of state parameter ψ on fractional order μ are introduced, and the state dependence of the direction of plastic strain increment is considered, thus reasonably describing the state-dependent dilatancy of sand. Furthermore, by introducing the state parameter into the Hooke's law, the elastic strain increment is obtained, and a non-orthogonal elastoplastic constitutive model which can describe the state dependence of sand is proposed. By reasonably predicting the results in triaxial drained and undrained tests on the Toyoura sand, it is proved that the established model can effectively capture the state-dependent mechanic characteristics of sand.

Lei Chen, Senlin Yang, Lei Guo et al.

Unknown geology ahead of the tunnel boring machine (TBM) brings a large safety risk for tunnel construction. Seismic ahead-prospecting using TBM drilling noise as a source can achieve near-real-time detection, meeting the requirements of TBM rapid drilling. Seismic wavefield retrieval is the key data processing step for the efficient utilization of TBM drilling noise. The traditional solution is based on cross-correlation to extract reflected waves, but the reference waves remain in the result, disturbing the imaging and interpretation of the adverse geology. To solve this problem, the deep learning method was introduced in wavefield retrieval to improve the accuracy of geological prospecting. We trained a deep neural network (DNN) with its strong nonlinear mapping capability to transform seismic data from TBM drilling noise to data from the active source. The issue lies in its features for this specific tunnel task, including the decay of the seismic signal with time and the incomplete spatial correspondence. Thus, we improved a classical DNN with the time constraint as an additional input, and an additional pre-decoder to enlarge the receptive field. Additionally, a loss function weighted by the ground truth and time constraint is improved to achieve an accurate retrieval of the effective signal, considering the little effective information in tunnel data. Finally, the workflow of the proposed method was given, and a dataset designed with reference to the field case was employed to train the network. The proposed method accurately retrieved the reflection signal with higher dominant frequencies, which helped improve the accuracy of imaging. Numerical simulations and imaging on typical geological models show that the proposed method can suppress reference waves and get more accurate results with fewer artifacts. The proposed method has been applied in the Gaoligongshan Tunnel and imaged two abnormal zones, providing meaningful geological information for TBM drilling and tunnel construction.

XIAO Jianzhang 1, LIU Yushan 1, WANG Di 2, LI Jian 1, WU Suaifeng 1, WANG Bo 1

The expansive soil is one of the recognized challenges in the field of geotechnical engineering. Based on the microbial technology, combined with the improved materials such as lime, cement and fly ash, the experimental researches on the engineering characteristics of composite improved expansive soil are conducted. The results show that: (1) The weak expansive soil is successfully changed into the non-expansive one by the microbial composite improvement of expansive soil, and the free expansion rate is reduced to 8% at the lowest, with a decrease of 84.31%. The engineering effect is good. (2) The decrease of the relative content of montmorillonite and the increase of the relative content of illite in the composite treated samples are the important reason for inhibiting the expansion and contraction characteristics. (3) When the bacterial solution of 20% is added to the expansive soil, the friction angle can increase by 23% compared to that at the same time last year. (4) In the case of composite improvement of expansive soil with bacterial solution, fly ash and lime, a low ratio combination of lime of 1% and fly ash of 2% is more advantageous for improving the strength.

DONG Jianhua 1, 2, YANG Bo 1, 2, TIAN Wentong 1, 2, 3, SU Shilin 1, 2, LIAN Bo 1, 2, LI Jianjun 4

Aiming at the main problems existing in the static load tests on pile foundations, a recyclable self-balancing detection device for the bearing capacity of the pile foundations is developed. The load transfer model for the test piles under the action of a new recyclable detection structure is established, and the load transfer matrix of pile body in a layered foundation is derived. The reliability of theoretical analysis is verified by the results of three-dimensional finite element calculation in practical engineering. The working mechanism of the structure is studied based on the data of load-displacement and pile axial force obtained from the field measurements. The results show that: (1) The new structure has high assembly degree, short test period, low energy consumption and small test space requirements, and is worth popularizing. (2) The axial load-displacement curves of the pile obtained from the theoretical analytical model are in agreement with the measured results, both of which are within the allowable error range compared with those of the load box test structure. (3) The accuracy of the bearing capacity measured by the new structure is improved by 3.5%. Therefore, the theoretical model and the new structure are of great applicability and popularization value in practical engineering.

Elizabeth Bjarnason, Mirko Morandini, Markus Borg et al.

The RET (Requirements Engineering and Testing) workshop series provides a meeting point for researchers and practitioners from the two separate fields of Requirements Engineering (RE) and Testing. The goal is to improve the connection and alignment of these two areas through an exchange of ideas, challenges, practices, experiences and results. The long term aim is to build a community and a body of knowledge within the intersection of RE and Testing, i.e. RET. The 2nd workshop was held in co-location with ICSE 2015 in Florence, Italy. The workshop continued in the same interactive vein as the 1st one and included a keynote, paper presentations with ample time for discussions, and a group exercise. For true impact and relevance this cross-cutting area requires contribution from both RE and Testing, and from both researchers and practitioners. A range of papers were presented from short experience papers to full research papers that cover connections between the two fields. One of the main outputs of the 2nd workshop was a categorization of the presented workshop papers according to an initial definition of the area of RET which identifies the aspects RE, Testing and coordination effect.

Tomohiko G. Sano, Emile Hohnadel, Toshiyuki Kawata et al.

Structures with artificial mechanical properties, often called mechanical metamaterials, exhibit divergent yet tunable performance. Various types of mechanical metamaterials have been proposed, which harness light or magnetic interactions, structural instabilities in slender or hollow structures, and contact friction. However, most of the designs are precisely engineered without any imperfections, in order to perform as programmed. Here, we study the mechanical performance of randomly stacked cylindrical-shells, which act as a disordered mechanical metamaterial. Combining experiments and simulations, we demonstrate that the stacked shells can absorb and store mechanical energy upon compression by exploiting large deformation and relocation of shells, snap-fits, and friction. Although shells are oriented randomly, the system exhibits robust mechanical performance controlled by friction and geometry. Our results demonstrate that the rearrangement of flexible components could yield versatile but predictive mechanical responses.

Jiangfeng Liu, Shijia Ma, Hongyang Ni et al.

The sealing performance of a bentonite barrier is highly dependent on its seepage characteristics, which are directly related to the characteristics of its pore structure. Based on scanning electron microscopy (SEM) and focused ion beam-SEM (FIB-SEM), the pore structure of bentonite was characterized at different scales. First, a reasonable gray threshold was determined through back analysis, and the image was binarized based on the threshold. In addition, binary images were used to analyze bentonite's pore structure (porosity and pore size distribution). Furthermore, the effects of different algorithms on the pore structure characterization were evaluated. Then, permeability calculations were performed based on the previous pore structure characteristics and a modified permeability prediction model. For permeability prediction based on the three-dimensional model, the effect of pore tortuosity was also considered. Finally, the accuracy of numerical calculations was verified by conducting macroscopic gas and alcohol permeability experiments. This approach provides a better understanding of the microscale mechanism of gas transport in bentonite and the importance of pore structures at different scales in determining its seepage characteristics.

Christoph Treude

Recommender systems are a valuable tool for software engineers. For example, they can provide developers with a ranked list of files likely to contain a bug, or multiple auto-complete suggestions for a given method stub. However, the way these recommender systems interact with developers is often rudimentary -- a long list of recommendations only ranked by the model's confidence. In this vision paper, we lay out our research agenda for re-imagining how recommender systems for software engineering communicate their insights to developers. When issuing recommendations, our aim is to recommend diverse rather than redundant solutions and present them in ways that highlight their differences. We also want to allow for seamless and interactive navigation of suggestions while striving for holistic end-to-end evaluations. By doing so, we believe that recommender systems can play an even more important role in helping developers write better software.

Sherlock A. Licorish, Christoph Treude, John Grundy et al.

Six months ago an important call was made for researchers globally to provide insights into the way Software Engineering is done in their region. Heeding this call we hereby outline the position Software Engineering in Australasia (New Zealand and Australia). This article first considers the software development methods practices and tools that are popular in the Australasian software engineering community. We then briefly review the particular strengths of software engineering researchers in Australasia. Finally we make an open call for collaborators by reflecting on our current position and identifying future opportunities

ZHANG Wen-gang, WANG Qi, CHEN Fu-yong et al.

In the reliability analysis of slope stability, the deterministic analysis method is usually used to calculate the safety factor to evaluate the stability of slope. However, the inherent spatial variability of rock mass properties cannot be considered and described adequately in traditional deterministic method, resulting in the inaccurate calculation of slope failure probability. Based on Hoek-Brown criterion and random finite difference method (RFDM), the reliability analysis of slope stability and random response of pile are discussed in this paper considering spatial variability of rock mass. The uniaxial compressive strength σci and material constant for the intact rock mi are regarded as random field variables and geological strength index GSI is assumed to be a random variable. The results show that the spatial variability of rock mass parameters has a significant effect on slope failure probability and pile response. Ignoring the spatial variability of rock mass parameters will overestimate slope failure probability and the mean value of the maximum bending moment of anti-slide pile, and underestimate the mean value of displacement at pile head. The results can provide design guidance for slope reinforcement as well as layout optimization of anti-sliding piles.