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

Peichao Zheng, Xianjun Tan, Zhihao Du et al.

Freezing and thawing processes play a crucial role in causing significant deformation and damage to layered soft rocks in cold region due to daily and seasonal temperature fluctuations. However, the frost heave mechanism of the rocks and their mechanical behaviors at the meso-scale still require further investigations. For this, we focused on carbonaceous slate reported in a high-altitude cold region, in terms of mineral composition, content, and microstructure. The strength and failure of mineral grain (MG) interfaces are studied using three-point-bending tests, in order to explore the evolution of mode I fracture toughness and tensile strength with the Dugdale-Barenblatt model and the Weibull distribution model. The results indicate that the damage of slate involves the initiation and propagation of microfracture networks at clay MG interfaces (bedding planes), driven by frost heave pressure at macroscopic and microscopic scales. This process causes the detachment of some MGs, resulting in fracture surfaces with a distinctive pulled-off planar structure. The hydrophilicity of clay MGs, interfacial strengths, and microfracture structures contribute to the freeze-thaw damage. As the number of freeze-thaw cycles increases, the effective area per unit decreases, leading to an exponentially decreasing in mode I fracture toughness and tensile strength at MG interfaces. Approximately 67% strength degradation occurs after 14 freeze-thaw cycles. This provides theoretical basis and experimental methods for better understanding the damage and deterioration behaviors of layered soft rocks in cold region under natural freeze-thaw cycles.

Jorge Melegati

The adoption of Generative AI (GenAI) suggests major changes for software engineering, including technical aspects but also human aspects of the professionals involved. One of these aspects is how individuals perceive themselves regarding their work, i.e., their work identity, and the processes they perform to form, adapt and reject these identities, i.e., identity work. Existent studies provide evidence of such identity work of software professionals triggered by the adoption of GenAI, however they do not consider differences among diverse roles, such as developers and testers. In this paper, we argue the need for considering the role as a factor defining the identity work of software professionals. To support our claim, we review some studies regarding different roles and also recent studies on how to adopt GenAI in software engineering. Then, we propose a research agenda to better understand how the role influences identity work of software professionals triggered by the adoption of GenAI, and, based on that, to propose new artifacts to support this adoption. We also discuss the potential implications for practice of the results to be obtained.

Ya-hui Yao, Xiao-feng Jia, Sheng-tao Li et al.

The karst geothermal reservoir in Xiong'an New Area is a representative example of an ancient buried hill geothermal system. However, published heat flow data are predominantly derived from the Cenozoic sedimentary cap. Due to the limited depth of borehole exploration, heat flow measurements and analyses of the Archean crystalline basement in the study area are rare. Further investigation of the heat flow and temperature field characteristics within the Archean crystalline basement beneath the karst geothermal reservoir is necessary to understand the vertical distribution of heat flow and improve the geothermal genetic mechanism in the area. The D01 deep geothermal scientific drilling parameter well was implemented in the Niutuozhen geothermal field of Xiong'an New Area. The well exposed the entire Gaoyuzhaung Formation karst geotheremal reservoir of the Jixian system and drilled 1,723.67 m into the Archean crystalline basement, providing the necessary conditions for determining its heat flow. This study involved borehole temperature measurements and thermophysical property testing of core samples from the D01 well to analyze the vertical distribution of heat flow. The findings revealed distinct segmentation in the geothermal gradient and rock thermophysical properties. The geothermal reservoir of Gaoyuzhuang Formation is dominated by convection, with significant temperature inversions corresponding to karst fracture developments. In contrast, the Archean crystalline basement exhibits conductive heat transfer. After 233 days of static equilibrium, the average geothermal gradients of the Gaoyuzhuang Formation and the Archean crystalline basement were determined to be 1.5°C/km and 18.3°C/km, respectively. These values adjusted to −0.8°C/km and 18.2°C/km after 551 days, with the longer static time curve approaching steady-state conditions. The average thermal conductivity of dolomite in Gaoyuzhuang Formation was measured as 4.37±0.82 W/(K·m), and that of Archean gneiss as 2.41±0.40 W/(K·m). The average radioactive heat generation rate were 0.30±0.32 μW/m3 for dolomite and 1.32±0.69 μW/m3 for gneiss. Using the temperature curve after 551 days and thermal conductivity data, the Archean heat flow at the D01 well was calculated as (43.9±7.0) mW/m2, While the heat flow for the Neogene sedimentary cap was estimated at 88.6mW/m2. The heat flow of Neogene sedimentary caprock is significantly higher than that of Archean crystalline basement at the D01 well, with an excess of 44.7 mW/m2 accounting for approximately 50% of the total heat flow in the Neogene sedimentary caprock. This is primarily attributed to lateral thermal convection within the high-porosity and high-permeability karst dolomite layer, and vertical thermal convection facilitated by the Niudong fault, which collectively contribute to the heat supply of the Neogene sedimentary caprock. Thermal convection in karst fissure and fault zone contribute approximately 50% of the heat flow in the Neogene sedimentary caprock. This study quantitatively revealed the vertical distribution of heat flow, providing empirical evidence for the genetic mechanism of the convection-conduction geothermal system in sedimentary basins.

WU Zhiqiang 1, 2 , SUN Zhilei 1, YIN Chunyang 1, XU Kai 1, 2

To address the technical challenge of low drainage-consolidation efficiency in bauxite residue with high clay content, the consolidation characteristics of two drainage configurations are systematically compared through vertical and horizontal drainage-consolidation model tests under graded vacuum loading. Combined with physico-mechanical tests, scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP) microstructural analyses, the response mechanisms between drainage interface efficiency and soil microstructure are elucidated. Under the staged vacuum loading, the horizontal drain configuration demonstrates 8.1% higher drainage volume and 17.7% shorter consolidation time compared to the conventional vertical drains. The horizontally drained soil exhibits superior uniformity, with smaller differential settlement and better load-bearing characteristics within the effective depth range. The post-consolidation measurements reveal the maximum variations of density and moisture content of 0.34 g/cm3 and 59.9% respectively in vertical drains, with the top layer penetration resistance being 8.7 times that of the bottom layer. In contrast, the horizontal drains show reduced variations of 0.16 g/cm3, 34.3%, and a 2.5-fold difference. The MIP and SEM analyses indicate that the vertically drained soil develops unimodal pore distribution dominated by micropores (< 0.1 μm), and the horizontally drained soil exhibits multimodal pore distribution including mesopores (1~100 μm). The study provides a novel approach for efficient dewatering of mineral slurries with high clay content, offering valuable engineering insights for the resource utilization of industrial solid wastes.

Bruce D. Popp

This paper reviews a paper from 1906 by J. Henri Poincaré on statistical mechanics with a background in his earlier work and notable connections to J. Willard Gibbs. Poincaré's paper presents important ideas that are still relevant for understanding the need for probability in statistical mechanics. Poincaré understands the foundations of statistical mechanics as a many-body problem in analytical mechanics (reflecting his 1890 monograph on The Three-Body Problem and the Equations of Dynamics) and possibly influenced by Gibbs independent development published in chapters in his 1902 book, Elementary Principles in Statistical Mechanics. This dynamical systems approach of Poincaré and Gibbs provides great flexibility including applications to many systems besides gasses. This foundation benefits from close connections to Poincaré's earlier work. Notably, Poincaré had shown (e.g. in his study of non-linear oscillators) that Hamiltonian dynamical systems display sensitivity to initial conditions separating stable and unstable trajectories. In the first context it precludes proving the stability of orbits in the solar system, here it compels the use of ensembles of systems for which the probability is ontic and frequentist and does not have an a priori value. Poincaré's key concepts relating to uncertain initial conditions, and fine- and coarse-grained entropy are presented for the readers' consideration. Poincaré and Gibbs clearly both wanted to say something about irreversibility, but came up short.

Haiqi Wu, Kai Xu

This paper investigates the relationship between categorical entropy and von Neumann entropy of quantum lattices. We begin by studying the von Neumann entropy, proving that the average von Neumann entropy per site converges to the logarithm of an algebraic integer in the low-temperature and thermodynamic limits. Next, we turn to categorical entropy. Given an endofunctor of a saturated A-infinity-category, we construct a corresponding lattice model, through which the categorical entropy can be understood in terms of the information encoded in the model. Finally, by introducing a gauged lattice framework, we unify these two notions of entropy. This unification leads naturally to a sufficient condition for a conjectural algebraicity property of categorical entropy, suggesting a deeper structural connection between A-infinity-categories and statistical mechanics.

Jincai SHEN

Objective Regarding conventional gas resources, research on the fracturing interference of adjacent wells has focused mainly on interference during the production process; the interference of adjacent wells is usually avoided by determining the rational spacing between wells, and the radius of influence is the key to determining a reasonable well spacing. The fracturing interference of shale gas adjacent wells involves various types, phenomena, results and control factors; however, there is no generally accepted description method or mechanism for studying the response characteristics of the fracturing interference of adjacent wells. Methods The Fuling shale gas field is taken as an example to discuss the response characteristics and mechanism of the fracturing interference of adjacent wells in shale gas. Results According to the impact on the recoverable reserves of parent wells, the fracturing interference of shale gas adjacent wells can be divided into three types: positive interference, noninterference and negative interference. The three types of interference are mainly related to the spacing of the child and parent wells, crossing layers, recovery percentage, formation pressure, stress difference and other factors. The closer the spacing and crossing layers between wells are, the greater the recovery degree of the parent wells or the lower the formation pressure is, the greater the difference between both sides of the stress of the child well becomes, and the greater the fracturing interference becomes. On the basis of the different results caused by fracturing interference, to avoid negative effects, shale gas development requires the formulation of reasonable well spacings, the shuttling of parent wells to restore the pressure until it stabilizes before fracturing, and the use of diverters during fracturing of new child wells. The generation mechanisms of fracturing interference are the degree of fracture and the overlap of artificial fracturing networks between child wells and parent wells. The ideal situation is that the fracturing network edge of the child wells just reaches the fracturing network edge of the older parent wells, which has a positive effect on increasing production; however, the noninterference type does not occur when the child wells' SRV is insufficient, nor does the negative interference type occur when the fracturing networks are connected between the child wells and parent wells. Conclusion The research results provide theoretical support for formulating reasonable fracturing interference prevention measures and have good guiding significance in industry.

WANG Chaohui 1, CHEN Shaochang 1, SONG Liang 1, 2, 3, WEN Penghui 1, CHEN Haoyu 1

To investigate the deformation characteristics of salt rock subgrade filler under the influences of temperature, ensure the stability of salt rock subgrade and promote the resource application of salt rock in subgrade engineering, the characteristics of phase transformation in brine and salt rock are analyzed. An orthogonal test method is used to investigate the deformation of salt rock filler under the interaction of multiple factors in a single cooling condition. The salt expansion accumulation laws of salt rock filler after multiple freeze-thaw cycles are studied. Based on the test section field monitoring, the deformation characteristics of salt rock subgrade in salt lake area are evaluated. The results show that the cooling curves of different brine concentrations do not exhibit any obvious subcooling stage, their balance and fluctuation are very short, and the brine phase transition temperature increases with the increasing concentration. The cooling curve of salt rock filler has an obvious stage of subcooling and temperature jump, and the phase transition temperature decreases with the increase of the mixed brine concentration. The deformation of salt rock filler under single cooling condition ranges from -0.09 mm to 0.18 mm. The order of influences of various factors on the deformation of salt rock filler is as follows: overburden load > brine content > maximum particle size > compaction. The lower the concentration of mixed brine under the freeze-thaw cycle, the greater the salt expansion of salt rock filler. The overburden load has a strong effect on inhibiting salt swelling of salt rock fillers. The field monitoring of the entity engineering shows that with the growth of monitoring time, the deformation of the salt rock subgrade shows a sinusoidal cyclical variation and decreases along the depth direction, and it has a strong linear correlation with temperature.

Thomas Speck

Inhomogeneous flows and shear banding are of interest for a range of applications but have been eluding a comprehensive theoretical understanding, mostly due to the lack of a framework comparable to equilibrium statistical mechanics. Here we revisit models of fluids that reach a stationary state obeying mechanical equilibrium. Starting from a non-local constitutive relation, we apply the idea of a "mechanical phase transition" and map the constitutive relation onto a dynamical system through an integrating factor. We illustrate this framework for two applications: shear banding in strongly thinning complex fluids and the coexistence of a solid with its sheared melt. Our results contribute to the growing body of work following a mechanical route to describe inhomogeneous systems away from thermal equilibrium.

Philip Metzger

In the companion paper ("Erosion rate of lunar soil under a landing rocket, part 1: identifying the rate-limiting physics", this issue) an equation was developed for the rate that lunar soil erodes under the exhaust of a landing rocket. That equation has only one parameter that is not calibrated from first principles, so here it is calibrated by the blowing soil's optical density curve during an Apollo landing. An excellent fit is obtained, helping validate the equation. However, when extrapolating the erosion rate all the way to touchdown on the lunar surface, a soil model is needed to handle the increased resistance to erosion as the deeper, more compacted soil is exposed. Relying on models derived from Apollo measurements and from Lunar Reconnaissance Orbiter (LRO) Diviner thermal inertia measurements, only one additional soil parameter is unknown: the scale of increasing cohesive energy with soil compaction. Treating this as an additional fitting parameter results in some degeneracy in the solutions, but the depth of erosion scour in the post-landing imagery provides an additional constraint on the solution. The results show that about 4 to 10 times more soil was blown in each Apollo landing than previously believed, so the potential for sandblasting damage is worse than prior estimates. This also shows that, with further development, instruments to measure the soil erosion during lunar landings can constrain the soil column's density profile complementary to the thermal inertia measurements, providing insight into the landing site's geology.

Cuiyun Gao, Xing Hu, Shan Gao et al.

With the advent of large language models (LLMs) in the artificial intelligence (AI) area, the field of software engineering (SE) has also witnessed a paradigm shift. These models, by leveraging the power of deep learning and massive amounts of data, have demonstrated an unprecedented capacity to understand, generate, and operate programming languages. They can assist developers in completing a broad spectrum of software development activities, encompassing software design, automated programming, and maintenance, which potentially reduces huge human efforts. Integrating LLMs within the SE landscape (LLM4SE) has become a burgeoning trend, necessitating exploring this emergent landscape's challenges and opportunities. The paper aims at revisiting the software development life cycle (SDLC) under LLMs, and highlighting challenges and opportunities of the new paradigm. The paper first summarizes the overall process of LLM4SE, and then elaborates on the current challenges based on a through discussion. The discussion was held among more than 20 participants from academia and industry, specializing in fields such as software engineering and artificial intelligence. Specifically, we achieve 26 key challenges from seven aspects, including software requirement & design, coding assistance, testing code generation, code review, code maintenance, software vulnerability management, and data, training, and evaluation. We hope the achieved challenges would benefit future research in the LLM4SE field.

Andrei A. Klishin, Joseph Bakarji, J. Nathan Kutz et al.

Recovering dynamical equations from observed noisy data is the central challenge of system identification. We develop a statistical mechanics approach to analyze sparse equation discovery algorithms, which typically balance data fit and parsimony via hyperparameter tuning. In this framework, statistical mechanics offers tools to analyze the interplay between complexity and fitness similarly to that of entropy and energy in physical systems. To establish this analogy, we define the hyperparameter optimization procedure as a two-level Bayesian inference problem that separates variable selection from coefficient inference and enables the computation of the posterior parameter distribution in closed form. Our approach provides uncertainty quantification, crucial in the low-data limit that is frequently encountered in real-world applications. A key advantage of employing statistical mechanical concepts, such as free energy and the partition function, is to connect the large data limit to thermodynamic limit and characterize the sparsity- and noise-induced phase transitions that delineate correct from incorrect identification. We thus provide a method for closed-loop inference, estimating the noise in a given model and checking if the model is tolerant to that noise amount. This perspective of sparse equation discovery is versatile and can be adapted to various other equation discovery algorithms.

DONG Fu-rui, WANG Shu-hong, HOU Qin-kuan

Statistical analysis and clustering of discontinuities existing in rock mass are the basis of rock mass engineering stability analysis. Considering that the mechanical and hydraulic properties of discontinuities are affected by many factors such as occurrence, trace length, aperture, roughness, and filling state, a multi-parameter dominant grouping method of rock mass discontinuities based on principal component analysis is proposed. Firstly, the principal component analysis method is used to select the criterion of the dominant grouping and calculate the weight value of its participation in similarity measurement. Secondly, the global optimal initial clustering center of the fuzzy C-means clustering algorithm is searched using the annealing genetic algorithm. Lastly, the objective function is established by minimizing the weighted sum of the distance between the discontinuities to be grouped and the clustering center, achieving the dominant grouping of multi-parameter rock mass discontinuity. Two hundred artificial discontinuities are divided into dominant groups using the multi-parameter method and the results are compared with other methods. The results show that this method has higher grouping accuracy. The method is applied to the multi-parameter dominant grouping of the measured discontinuities of Huayang Tunnel of Chongqing Third Ring Expressway. The grouping results are reasonable and reliable, which further verifies that the proposed method has a significant engineering application value.

Hao Hong, Jianwen Dai, Hua Wang et al.

In the early stage of offshore oilfield development, due to the lack of drilling, limited data admission, and lack of dynamic data, there is great uncertainty in the understanding of oilfield reserves. With increased degree of development, production is usually inconsistent with reserves, and reserve re-evaluation is an important way to resolve this problem. In order to improve the development efficiency and reduce costs, offshore oilfields are dominated by horizontal wells, resulted in limited data acquisition. Therefore, new horizontal well data has become the key to obtainnew geological reservoir parameters and improve the accuracy of reserve estimation. In order to further obtain reliable reserve evaluation results and resolve the dynamic and static contradictions of the oilfield, based on analyzing the main controlling parameters of reserve change in the Pearl River Mouth Basin, this study fully excavates the role of horizontal development wells in improving the accuracy of primary controlling parameters.Our results show that the oil-bearing area and effective thickness are the most uncertain in the reserve assessment, and cause the change of reserves. Horizontal development well is critical in improving the production capacity of the oilfield, determining the lower limit of effective thickness, investigating microstructure, and identifying lithological boundary and fluid interface, etc. In the case of limited data access, the utilizationof horizontal development wells can effectively improve the accuracy of major controlling parameters to obtain relatively reasonable geological reserves, and solve the dynamic contradictions of oilfield production. It also points out the direction for late exploration and development of oilfields. Application examples from multiple oil fields in the eastern South China Sea also confirm this understanding.

H.C. Nguyen, T. Vo-Minh

The node-based smoothed finite element method (NS-FEM) is shortly presented for calculations of the static and seismic bearing capacities of shallow strip footings. A series of computations has been performed to assess variations in seismic bearing capacity factors with both horizontal and vertical seismic accelerations. Numerical results obtained agree very well with those using the slip-line method, revealing that the magnitude of the seismic bearing capacity is highly dependent upon the combinations of various directions of both components of the seismic acceleration. An upward vertical seismic acceleration reduces the seismic bearing capacity compared to the downward vertical seismic acceleration in calculations. In addition, particular emphasis is placed on a separate estimation of the effects of soil and superstructure inertia on each seismic bearing capacity component. While the effect of inertia forces arising in the soil on the seismic bearing capacity is non-trivial, and the superstructure inertia is the major contributor to reductions in the seismic bearing capacity. Both tables and charts are given for practical application to the seismic design of the foundations.

Yujun Cui

The soil–atmosphere interaction was investigated through laboratory testing, field monitoring and numerical monitoring. In the laboratory, the soil water evaporation mechanisms were studied using an environmental chamber equipped with a large number of sensors for controlling both the air parameters and soil parameters. Both sand and clay were considered. In case of sand, a dry layer could be formed during evaporation in the near surface zone where the suction corresponded to the residual volumetric water content. The evaporative surface was situated at a depth where the soil temperature was the lowest. In case of clay, soil cracking occurred, changing the evaporative surface from one-dimensional to three-dimensional nature. The suctionbased evaporation model was adapted to take these phenomena into account by adopting a function of dry layer evolution in the case of sand and by adopting a surface crack ratio and a retative humidity ratio in the case of clay. In the field, the volumetric water content, and the suction as well as the runoff were monitored for an embankment constructed with lime/cement treated soils. It appeared that using precipitation data only did not allow a correct description of the variations of volumetric water content and suction inside the soils, the consideration of water evaporation being essential. It was possible to use a correlation between precipiration and runoff. The hydraulic conductivity was found to be a key parameter controlling the variations of volumetric water content and suction. For the numerical modelling, a fully coupled thermohydraulic model was developed, allowing analyzing the changes in temperature, volumetric water content and suction of soil, with the upper boundary conditions at the interface between soil and atmosphere determined using meteorological data. Comparison between simulations and measurements showed the performance of such numerical approach.

Shu Zhang, Huiming Tang, Wenping Gong et al.

Landslide forecasting and prediction is a frontier scientific issue that has received widespread attention in the field of geohazard prevention and control. The current research framework focuses on the deformation behavior characteristics and external dynamic factors of landslides and faces the dual bottleneck problems of low universality and low prediction accuracy.Based on the current research status, this paper systematically clarifies the connotation of the rheological-mechanical behavior and strength weakening effect of the sliding zone, explicates the evolution mechanism of the progressive failure of the landslide, summarizes the types of landslide prediction models, and introduces the typical models among them.Based on the comprehensively existing achievements, it is pointed out that the main problems of the current research are: ①the physical-mechanical models of landslide evolution are required to be extended; ②the prediction and forecasting models fail to fully integrate with landslide evolution and physical-mechanical model; ③the compatibility problem between physical-mechanical model prediction and multi-field monitoring data have not been practically solved. Given the above problems, the challenges of landslide prediction and forecasting models based on physical-mechanical processes are elaborated. Based on multidisciplinary integration and intersection, a new research strategy for landslide forecasting study is proposed. The new strategy requires the establishment of a physical-mechanical model of the landslide evolution process based on the structural properties and rheological-mechanical behavior of the slip zone. On this basis, a numerical forecasting mode for landslides is established by closely integrating real-time multi-field monitoring data that enables real-time dynamic updating of landslide physical-mechanical processes. This strategy is designed to achieve a theoretical and technical breakthrough.

Dalton A R Sakthivadivel

Bayesian mechanics is a new approach to studying the mathematics and physics of interacting stochastic processes. Here, we provide a worked example of a physical mechanics for classical objects, which derives from a simple application thereof. We summarise the current state of the art of Bayesian mechanics in doing so. We also give a sketch of its connections to classical chaos, owing to a particular $\mathcal{N}=2$ supersymmetry.

Wilhelm Hasselbring

In empirical software engineering, benchmarks can be used for comparing different methods, techniques and tools. However, the recent ACM SIGSOFT Empirical Standards for Software Engineering Research do not include an explicit checklist for benchmarking. In this paper, we discuss benchmarks for software performance and scalability evaluation as example research areas in software engineering, relate benchmarks to some other empirical research methods, and discuss the requirements on benchmarks that may constitute the basis for a checklist of a benchmarking standard for empirical software engineering research.

Murtala Umar, Khairul Anuar Kassim, Kenny Tiong Ping Chiet