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

Shimul Akhanjee

The statistical mechanics of particles that populate indistinguishable energy states is explored. In particular, the mathematical treatment of the microstates differs from conventional statistical mechanics where the energy levels or states are universally treated as distinguishable, and differentiated by unique quantum numbers, or addressed by distinct spatial locations. Results from combinatorial counting problems are adapted to derive exact distribution functions for both classical and quantum particles at high degeneracy levels. Classical particles exhibit a definitive glass transition, similar to supercooled liquids where where the configurational entropy vanishes below a finite temperature $T_K$.

Zhanbo Cheng, Xueyu Geng

Chengzeng Yan, Tie Wang

A.S. Devapriya, T. Thyagaraj

PENG Hao 1 , HAN Yu 1, LIANG Ming 1 , XIE Weiwei 1, 2, ZHU Menglong 1, SONG Guanxian 1, HUANG Nenghao 1, WU Menglan 1, ZENG Nongjian 1, XIE Yunze 3

In response to the current situation of static fragmentation in tunnel construction safety assessment system, insufficient multi-source information, and the challenge of ensuring the reliability of assessment methods, this paper proposes an integrated dynamic safety assessment technology and engineering application system for tunnel construction based on multi-source information fusion. With a multi-dimensional and multi-scale concept, the tunnel construction cycle is divided into three nested scales: survey and design, advance prediction, and excavation monitoring, as well as three source dimensions under each scale: geological information, construction information, and prediction information, to form a multi-source safety information assessment index system. This system can meet the requirements of survey and design in alignment with construction progress: two overall risk assessments under the advance prediction scale, and various specialized construction safety assessments under the excavation monitoring scale. To enhance the rationality and reliability of safety assessment results, the D-S evidence theory serves as the fusion framework. The interval Euclidean distance method and average evidence method optimize the basic probability assignment calculation and conflicting evidence fusion in the multi-source information fusion process. The implementation of this comprehensive dynamic safety assessment method and system is illustrated through a tunnel engineering project. Results show consistency between the assessment outcomes and actual site conditions. Further discussion, comparison, and verification demonstrate its rationality and reliability, it can provide valuable reference and practical guidance for tunnel construction safety assessment and control.

Mohamed Ayeldeen, Abdelazim Negm, Mostafa El-Sawwaf et al.

Hua LUO, Pan GUO, Li LIU et al.

Objective Lead-zinc mineralization is widely distributed in southwestern Hubei Province, but no large deposits have been found thus far, and there is a lack of systematic studies on metallogenic systems. Methods The C-H-O-S-Pb isotope analysis and the homogenization temperature of fluid inclusions of lead-zinc-fluorite ore in the Geleche area of Laifeng were conducted. Results The results show that the homogenization temperature of fluid inclusions in fluorite and calcite is concentrated between 137-170℃, and the variation range of salinity is 11.46%-16.89%. It is a NaCl-H2O system with low temperature and medium and low salinity. The main source may be metamorphic dehydration of rock formations containing sedimentary sulfate (marine sediments). The δ34S content ranges from 9.5‰ to 11.8‰, with an average of 10.92‰. 206Pb/204Pb < 18.20, 207Pb/204Pb>15.60, and 208Pb/204Pb < 39.00, and the floating ratio is small and high μ and high ω. Conclusion The sulfur and lead sources are mainly from the Ordovician and Cambrian ore-bearing strata in the Paleozoic sedimentary basin of the upper crust. Syngenetic sedimentary diagenesis and epigenetic medium- and low-temperature hydrothermal transformation are the dominant genetic types of the Geleche mining area. Compared with the typical lead-zinc deposits in the Yangtze Platform of West Hubei and Hunan, they have great similarity and obvious differences in metallogenic fluid, Paleozoic sedimentary environment and tectonic background.

ZHU Jungao 1, CHEN Ge 1, WANG Tao 1, XIA Yong 2, PENG Wenming 2, LUO Qixun 2

A new simple shear apparatus is invented for fine grained soil based on the existing designs. Some rectangular- stacked steel laminations are used for the new simple shear apparatus. The internal dimensions of the steel laminations are 100 mm in length and 40 mm in width. It effectively eliminates the common issues such as sample tilting and uneven stress distribution during shear testing compared to the conventional simple shear apparatuses. The pin type deformation control rod can ensure uniform shear deformation of the specimen. The guiding side plate around the specimen chamber controls the direction of the shear force. The new lever support structure effectively solves the problem of load rod force transmission because the lever is tilted. The simple shear apparatus is featured with stable structure and easy operation. It combines the stress/strain control functions into one unit, allowing for the uniform shear testing of fine-grained soils. The shear strength tests and shear creep tests on clay are carried out using the novel simple shear apparatus. Meanwhile, the parameters of shear strength and the laws of creep are analyzed. The test results validate the good performance of the novel simple shear apparatus.

Yong-Kang Qiao, Fang-Le Peng, Yun-Hao Dong et al.

Urban underground infrastructures (UUIs) are a vital component of built capital for urban sustainability. However, many cities are now home to a multitude of disused or underutilized UUIs, not least aged purpose-built underground facilities, causing a waste of valuable underground space resource assets. In the process of urban renewal, adaptive reuse can be an attractive solution to breathe new life into underutilized UUIs, while addressing some of the modern problems of the built environment by an economically feasible means. Nevertheless, there is a prevalent absence in the current literature of the overarching planning and decision-making approaches for an adaptive reuse development of underutilized UUIs. With the intention of addressing this shortfall, this paper first lays out development strategies, then sets the generic patterns for adaptive reuse of disused or underutilized UUIs. Taking the city of Qingdao, China as a case study, detailed planning and decision-making approaches with the aid of multi-source data and spatial analysis tools are presented. It is anticipated that the findings of this research will assist the adaptive reuse development of UUIs in providing theoretical guidance and empirical evidence, thereby enhancing the role of urban underground space use in contributing to urban revitalization and urban sustainability.

Sergio Rico

Case studies are a popular and noteworthy type of research study in software engineering, offering significant potential to impact industry practices by investigating phenomena in their natural contexts. This potential to reach a broad audience beyond the academic community is often undermined by deficiencies in reporting, particularly in the context description, study classification, generalizability, and the handling of validity threats. This paper presents a reflective analysis aiming to share insights that can enhance the quality and impact of case study reporting. We emphasize the need to follow established guidelines, accurate classification, and detailed context descriptions in case studies. Additionally, particular focus is placed on articulating generalizable findings and thoroughly discussing generalizability threats. We aim to encourage researchers to adopt more rigorous and communicative strategies, ensuring that case studies are methodologically sound, resonate with, and apply to software engineering practitioners and the broader academic community. The reflections and recommendations offered in this paper aim to ensure that insights from case studies are transparent, understandable, and tailored to meet the needs of both academic researchers and industry practitioners. In doing so, we seek to enhance the real-world applicability of academic research, bridging the gap between theoretical research and practical implementation in industry.

Yujun Cui

Ding Wang, Manchao He, Liangjiu Jia et al.

Nowadays, the development of novel metallic materials for rock support have attracted research interests since they can significantly improve the deformation and energy absorption capacities of rock bolts. Although previous studies proved the importance and mechanical advantages of utilizing high-strength and high-toughness (HSHT) steels in rock support, there is no systematic analysis to reveal the essential energy absorption parameter and the guidelines for further development of metallic rock support materials. This paper analyzes the energy absorption characteristics of novel HSHT steels (negative Poisson's ratio (NPR) and twinning-induced plasticity (TWIP) steels) in comparison with conventional rock support materials. A physically based crystal plasticity (CP) model was set up and calibrated to study the effect of strain hardening rate (SHR). Meanwhile, the roles of underlying physical mechanisms, i.e. the dislocation density and twin volume fraction, were studied. The results show that the improvement of energy absorption density (EAD) is essential for further development of rock support materials, besides the increase of energy absorption rate (EAR) for previous development of conventional rock support materials. The increase of EAD requires increases of both strength and deformation capacity of materials. For HSHT steels, the decrease of SHR has a positive effect on the improvement of EAD. In addition, the increase of EAD is followed by the increase of twin volume fraction and the decrease of plastic Poisson's ratio which can promote deformation plasticity of materials. Meanwhile, the increase of EAR is correlated with the accumulation of dislocation density, which can increase the strength of materials. This paper provides the theoretical basis and guidelines for developing rock support materials in deep underground engineering and other related fields.

Lipiński Mirosław J., Wdowska Małgorzata, Puspitaningrum Intan

Since in the field of research concerning liquefaction phenomenon, the largest database exists for triaxial tests, this type of apparatus was selected as the most relevant. Available data concerning laboratory research on liquefaction tests for identification of undrained response of sand indicated that the results are very sensitive to even smallest incorrectness in the testing procedure. Besides, due to a complex nature of liquefaction phenomenon, it was considered prudent to undertake some efforts directed to increase the objectivity of tests. Therefore, before commencement of the actual test program for investigation of undrained response of soil, it is necessary to carry out some preparatory experimental work consisting of application of indispensable modification necessary for enhancement of a quality of a triaxial test. The paper presents the key issues pertaining to the implementation of the experiment. Significance of these modifications for desired characteristics is emphasized. Relevance of some upgrading of the equipment for liquefaction tests is exemplified.

Cexuan Liu, Fengshou Zhang, Quan Wang et al.

The Hutubi gas field was put into production in 1998 and then converted into an underground gas storage (UGS) facility in 2013, and since then a cluster of earthquakes associated with seasonal injection and extraction activities have been recorded nearby. To evaluate the fault stability and seismic potential, we established a pseudo-3D geomechanical model to simulate the process of seasonal injection and extraction. Reservoir pore pressures from 1998 to 2019 were obtained through multiphase reservoir simulation and validated by history matching the field injection and production data. We then imported pore pressures into the geomechanical model to simulate the poroelastic perturbation on faults for over 20 years. The fidelity of this model was validated by comparing the simulated surface deformation with global positioning system (GPS) measured data. We used Coulomb failure stress (CFS) as the indicator for the likelihood of fault slippage. The simulation results show that the location of the induced earthquake cluster was within the positive Coulomb stress perturbation (ΔCFS) area, in which fault slippage was promoted. In addition, ΔCFS at the earthquake location kept increasing after the injection began. These findings could explain the induced earthquakes with the Coulomb failure stress theory. Furthermore, we conducted a parameter sensitivity study on the dominant factors such as the maximum operating pressure (MOP), frictional coefficient, and dip angle of the pre-existing fault. The results indicate that the magnitude of ΔCFS caused by seasonal injection and extraction decreases with distance; MOPs are constrained to 32.9, 36.2, and 39.5 MPa according to different ΔCFS thresholds; the critical dip angle ranges are 0–20° and 80°–100°; and strengthening the fault friction can either increase or decrease the seismic potential. This study can help determine the MOP for Hutubi underground gas storage (HTB UGS) and provide a framework for simulating the potential causes of induced seismicity for other sites.

Lvyang Yang, Jiankang Zhang, Huaiqiang Li et al.

The digitization of engineering drawings is crucial for efficient reuse, distribution, and archiving. Existing computer vision approaches for digitizing engineering drawings typically assume the input drawings have high quality. However, in reality, engineering drawings are often blurred and distorted due to improper scanning, storage, and transmission, which may jeopardize the effectiveness of existing approaches. This paper focuses on restoring and recognizing low-quality engineering drawings, where an end-to-end framework is proposed to improve the quality of the drawings and identify the graphical symbols on them. The framework uses K-means clustering to classify different engineering drawing patches into simple and complex texture patches based on their gray level co-occurrence matrix statistics. Computer vision operations and a modified Enhanced Super-Resolution Generative Adversarial Network (ESRGAN) model are then used to improve the quality of the two types of patches, respectively. A modified Faster Region-based Convolutional Neural Network (Faster R-CNN) model is used to recognize the quality-enhanced graphical symbols. Additionally, a multi-stage task-driven collaborative learning strategy is proposed to train the modified ESRGAN and Faster R-CNN models to improve the resolution of engineering drawings in the direction that facilitates graphical symbol recognition, rather than human visual perception. A synthetic data generation method is also proposed to construct quality-degraded samples for training the framework. Experiments on real-world electrical diagrams show that the proposed framework achieves an accuracy of 98.98% and a recall of 99.33%, demonstrating its superiority over previous approaches. Moreover, the framework is integrated into a widely-used power system software application to showcase its practicality.

Arnold Bachrach, Yaniv Edery

Pressurized fluid injection into underground rocks occurs in applications like carbon sequestration, hydraulic fracturing, and wastewater disposal, and may lead to human-induced earthquakes and surface uplift. The fluid injection raises the pore pressure within the porous rocks, while deforming them, yet this coupling is not well understood as experimental studies of rocks are usually limited to postmortem inspection and cannot capture the complete deformation process in time and space. We investigate injection-induced deformation of a unique rock-like transparent medium mimicking the deformation of sandstone, yet under low pressure. By incorporating within this artificial rock fluorescent microspheres we capture its internal deformation in real time during the pressurized flow. We then modify the theory of poroelasticity to model accurately and without any fitting parameters the internal elastic deformations, hence providing a physical mechanism for the process. Moreover, our results demonstrate and validate the underling assumptions of the poroelastic theory for fluid injection in rock-like materials. Our results are relevant for understanding human-induced earthquakes and injection induced surface uplift, as they decouple the role of the pressurized flow from the rock deformation through the poroelastic theory.

Ian A. Cosden

The Princeton Research Software Engineering Group has grown rapidly since its inception in late 2016. The group, housed in the central Research Computing Department, comprised of professional Research Software Engineers (RSEs), works directly with researchers to create high quality research software to enable new scientific advances. As the group has matured so has the need for formalizing operational details and procedures. The RSE group uses an RSE partnership model, where Research Software Engineers work long-term with a designated academic department, institute, center, consortium, or individual principal investigator (PI). This article describes the operation of the central Princeton RSE group including funding, partner & project selection, and best practices for defining expectations for a successful partnership with researchers.

Guruprasad Deshpande, Mangesh Goswami, Jayesh Kolhe et al.

Soil moisture (SM) is referred to as a finite amount of water molecules within the pore spaces and it is a crucial parameter of Hydro-Meteorological processes. The behaviour of soil moisture water changes spatially and temporally in response to topography, soil characteristics, and climate[1]. Soil moisture is overseen by various hydro-meteorological factors that vary vertically with depth, laterally across terrestrial shapes, and temporarily in feedback to the climate. The precise monitoring and quantification of high-resolution surface and subsurface soil moisture observations are very important [13]. This paper highlights the outcomes of the fieldwork carried out at IITM, Pune, wherein we have developed a soil moisture and temperature measurement system using Raspberry Pi and the Internet of things (IoT). The development is classified into three stages, the first stage includes the assembly of the sensor with the microprocessor. The deployment of the low-cost system, data generation, and communication through a wireless sensor network is part of the second stage. Finally, the third stage includes real-time data visualization using a mobile application and data server for analysing soil moisture and temperature. The soil moisture profile obtained through the sensor deployed is highly correlated (r=.9) with in-situ gravimetric observations, having a root mean square error (RMSE) of about 3.1%. Similarly, the temperature observations are well-matched with the in-situ standard temperature observation. Here we present the preliminary results and compare the accuracy with the state-of-the-art sensors.

Seong-Woo Moon, Hyun-Seok Yun, Yong-Seok Seo

Although friction characteristics of fault gouge are important to understand reactivation of fault, behavior of earthquake, and mechanism of slope failure, analysis results of fault gouge have low accuracy mostly than those of soils or rocks due to its high heterogeneity and low strength. Therefore, to improve the accuracy of analysis results, we conducted simple regression analysis and structural equation model analysis and selected major influential factors of friction characteristics among many factors, and then we deduced advanced regression model with the highest coefficient of determination (R2) via multiple regression analysis. Whereas most coefficients of determination in simple regression analysis are below 0.3–0.4, coefficient of determination in multiple regression analysis is remarkably large as 0.657.

Heidar Ghafari, Manouchehr Gorji

Introduction Although soil erosion in natural ecosystems takes place very slowly, yet its cumulative effects on soil productivity are significant in the long term, and even very low rates of erosion cause loss of considerable amounts of soil during the course of many years. Based on statistics presented during the past 40 years, about 30% of agricultural lands in the world have lost their fertility due to erosion and have turned into non-arable lands (Pimentel and Burgess, 2013), and approximately 75 million tons of fertile agricultural soil is lost every year (Eswaran et al., 2001). In another report, it has been stated that about 10 million hectares of agricultural lands in the world lose their productive capacity annually and become non-cultivable lands (Lal, 2001).Materials and MethodsSWAT model was used to simulate the effect of soil erosion on dry wheat yield. For this purpose, after model calibration and validation, the following five scenarios were defined to quantify the effects of erosion on rainfed wheat yield: (1) current soil depth, (2) removing 5 cm, (3) removing 10 cm, (4) removing 15 cm, (5) and removing 20 cm of current topsoil depth in soil database.Accordingly, a regression relation was established between surface soil erosion and wheat yield.Results and Discussion Regression analysis showed that for each centimeter of soil erosion, the yield of rainfed wheat was reduced by 15.1 kg equal to 0.5%. The model results showed that the average specific erosion in the agricultural lands of the region is about 10 t/ha (0.77 mm/year). Assuming that the erosion rate is constant over 100 years, about 77 mm of soil is destroyed, equivalent to a loss of 116 kg/ha of dryland wheat yield. Considering the area under wheat cultivation (about 50,000 ha) in the study region, it is estimated that 580 tons of wheat per year will be destroyed by erosion.Conclusion SWAT model was used to assess the effect of erosion on crop yield. The gradual decrease in horizon A depth of input soil data to the model showed that with a decrease in the soil depth per 10 cm, the average yield decreased by 5%. It is suggested that in subsequent studies, the results of this method can be compared and validated with the comparative plot method, as the best field method in evaluating the effect of erosion on yield.