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Full-Text Articles in Geotechnical Engineering

Effect Of Waste Covid-19 Masks On Compaction Characteristics Of Silty-Clay Soil, Sydney K. Lawson May 2024

Effect Of Waste Covid-19 Masks On Compaction Characteristics Of Silty-Clay Soil, Sydney K. Lawson

Honors College Theses

The present study aims to explore the effect of adding shredded waste Covid-19 masks to silty-clay soil on the soil’s compaction characteristics for beneficial use in embankment, the subgrade of roadways, or backfill. This was accomplished by using two different types of masks: blue surgical masks and KN95 masks. Both mask types were hand shredded into half-inch sections using safety-scissors. The maximum dry density (MDD) and optimum moisture content (OMC) are the two most important compaction characteristics, and they were determined by the Standard Proctor Compaction Test (ASTM D698 / AASHTO T99). The change of both the MDD and OMC …


Performance Assessment Of Microencapsulated Phase Change Materials With Low To High Thermoregulation Range In Asphalt Binder, Anil Kumar Baditha, Ayyaz Fareed Mar 2024

Performance Assessment Of Microencapsulated Phase Change Materials With Low To High Thermoregulation Range In Asphalt Binder, Anil Kumar Baditha, Ayyaz Fareed

Graduate Student and Postdoctoral Fellow Symposium

Asphalt pavements face significant challenges due to low temperature cracking and rutting caused by extreme temperature fluctuations and traffic loading. These issues result in higher maintenance costs and reduced service life of the pavements. To address this, researchers explored the use of Microencapsulated Phase Change Materials (MPCMs) to induce thermoregulation in asphalt pavements. However, the existing research focused on high-temperature performance of binders, highlighting the need of research on evaluating the low-temperature performance. Therefore, the study aims to evaluate the impact of incorporating MPCMs on low to high temperature performance of binders. Three types of MPCMs were incorporated into asphalt …


Experimental Study On Shear Strength Of Unsaturated Soil Over A Wide Suction Range And Its Prediction, Geng Niu, Xiao-Feng Zhu, Jun-Xing Li, Meng-Yuan Lü, Li-Qi An, Zi-Han Chen Feb 2024

Experimental Study On Shear Strength Of Unsaturated Soil Over A Wide Suction Range And Its Prediction, Geng Niu, Xiao-Feng Zhu, Jun-Xing Li, Meng-Yuan Lü, Li-Qi An, Zi-Han Chen

Rock and Soil Mechanics

In this paper, the experimental studies on the water retention and strength properties of unsaturated weakly expansive soil in a wide suction range were carried out, and a strength model of unsaturated soil over a wide suction range was proposed. The results show that in the wide suction range, the stress‒strain curve increases with the increase of suction. The strain hardening occurs in the low suction range, while the strain softening appears in the high suction range. In the low suction range, the sample presents shear contraction, while in the high suction range, the sample begins to show a shear …


Energy Evolution Of Unloading Confining Pressure And Dissipative Energy Damage Constitutive Model Of Coal-Rock Combination, Wen-Kai Ru, Shan-Chao Hu, Di-Yuan Li, Jin-Yin Ma, Chen-Xi Zhang, Ping-Kuang Luo, Hao Gong, Ao-Hui Zhou Feb 2024

Energy Evolution Of Unloading Confining Pressure And Dissipative Energy Damage Constitutive Model Of Coal-Rock Combination, Wen-Kai Ru, Shan-Chao Hu, Di-Yuan Li, Jin-Yin Ma, Chen-Xi Zhang, Ping-Kuang Luo, Hao Gong, Ao-Hui Zhou

Rock and Soil Mechanics

In coal mining, the excavation of a coal-rock roadway and a thin coal seam will inevitably cause radial unloading of the coal-rock combination system. The radial unloading phenomenon is often accompanied by the rapid accumulation and release of energy, so it is necessary to investigate the energy evolution law of coal-rock combination specimens under the unloading confining pressure condition. To this end, the unloading confining pressure tests with different unloading rates were carried out for the coal-rock combination specimens. The results show that: (1) The axial loading and constant stress stages are the main energy storage stages of the combination …


Reliability Of Offshore Plate Anchor Design In Sand For Uplift Limit State, Yu-Ting Li, Xiao-Bin Chen, Peng-Peng He Feb 2024

Reliability Of Offshore Plate Anchor Design In Sand For Uplift Limit State, Yu-Ting Li, Xiao-Bin Chen, Peng-Peng He

Rock and Soil Mechanics

The offshore wind industry needs to move towards floating offshore wind turbines (FOWTs) that are secured to the seabed with anchoring systems in order to harness the more substantial amounts of offshore wind resources available in deep waters. The design of the anchoring system for FOWTs is crucial to ensure stability and safety in challenging offshore conditions. As a simplified reliability- based design approach, the partial safety factor method remains important in current offshore foundation design practice, but its effectiveness in achieving the required target safety level still needs to be examined. To achieve this end, a reliability analysis is …


Analysis Of Factors Affecting Permeability Of Calcareous Sand In Salt Solution Environment, Si-Wei Zheng, Ming-Jian Hu, Yu-Long Huo, Yu Li Feb 2024

Analysis Of Factors Affecting Permeability Of Calcareous Sand In Salt Solution Environment, Si-Wei Zheng, Ming-Jian Hu, Yu-Long Huo, Yu Li

Rock and Soil Mechanics

Permeability is the capacity of a soil for transmitting a fluid, e.g., a salt solution, through soil pores. The permeability coefficient K is an important measurement of the soil permeability, which is affected by various factors. The existing research on the permeability of sandy soil is basically carried out in the freshwater environment. However, the calcareous sand is a typical marine sedimentary sand, which is deposited in the seawater environment with certain salt concentrations. In order to investigate the influence of void ratio, particle size and concentration of the salt solution on the permeability of calcareous sand in a salt …


Strength Model Of Anisotropic Rocks Based On Hoek-Brown Criterion, Guo-Xiao Li, Hang-Long Wang, Jun Peng, Lin-Fei Wang, Bi-Bo Dai Feb 2024

Strength Model Of Anisotropic Rocks Based On Hoek-Brown Criterion, Guo-Xiao Li, Hang-Long Wang, Jun Peng, Lin-Fei Wang, Bi-Bo Dai

Rock and Soil Mechanics

In order to improve the applicability of Hoek-Brown failure criterion and reduce subjectivity in the determination of geological strength index (GSI) value for anisotropic rocks, a modified Hoek-Brown failure criterion is proposed, which considers the variation of the GSI value with the bedding angle of anisotropic rocks. Triaxial compression test data of anisotropic rocks with different bedding angles were first collected. The results show that the peak strength of anisotropic rocks exhibits a U-shaped relation with bedding angle . Then, the rock specimen with the bedding angle  = 0º is defined as the intact rock. The uniaxial compressive strength …


Correlation Between Macro And Micro Mechanical Parameters Of Marble Based On Nanoindentation Experiment, Xian-Hui Chen, Yi Cheng, Xin-Yue Xie, Mi-Mi Chen Feb 2024

Correlation Between Macro And Micro Mechanical Parameters Of Marble Based On Nanoindentation Experiment, Xian-Hui Chen, Yi Cheng, Xin-Yue Xie, Mi-Mi Chen

Rock and Soil Mechanics

Nanoindentation experiment is an important means to study micro mechanical properties of rock. Up to now only a few studies have discussed the correlation between the micro mechanical properties of rock and various macroscopic strengths of the rock. Firstly, the nanoindentation experiments on four different kinds of marble were carried out by the continuous stiffness measurement technique to obtain the micro mechanical parameters of dolomite and calcite. Secondly, the microscopic data scale was upgraded by Mori-Tanaka method to obtain the homogenized elastic modulus and Poisson’s ratio. Finally, the correlation between the microscopic parameters and the macroscopic mechanical experiment results was …


Fatigue Analysis Of Jacket Foundations For Offshore Wind Turbines, Yue-Ming Du, De-Qiong Kong, Si-Liu Wang, Bin Zhu Feb 2024

Fatigue Analysis Of Jacket Foundations For Offshore Wind Turbines, Yue-Ming Du, De-Qiong Kong, Si-Liu Wang, Bin Zhu

Rock and Soil Mechanics

Jacket foundations are considered as the most promising solution for offshore wind turbines (OWTs), due to its large lateral stiffness and adaptability to different marine environments. Nowadays, the study on jacket foundations mainly focuses on the bearing and deformation behavior, with significantly less attention being paid to their fatigue damage. Besides, the actual pile-soil interaction is always ignored when assessing the fatigue damage or fatigue life of the foundations for OWTs. This paper presents the development of a three-dimensional numerical model of tetrapod piled jacket foundations, with the interaction between the corner piles and the soil being implemented into it. …


Meso-Fracture Evolution Characteristics Of Freeze-Thawed Sandstone Based On Discrete Element Method Simulation, Yong-Jun Song, Yin-Wei Sun, Chen-Jing Li, Hui-Min Yang, Lei-Tao Zhang, Li-Jun Xie Feb 2024

Meso-Fracture Evolution Characteristics Of Freeze-Thawed Sandstone Based On Discrete Element Method Simulation, Yong-Jun Song, Yin-Wei Sun, Chen-Jing Li, Hui-Min Yang, Lei-Tao Zhang, Li-Jun Xie

Rock and Soil Mechanics

To investigate the mesoscopic damage accumulation and the loading-induced fracture process in freeze-thawed rocks, a method coupling water-ice particle phase transition and expansion based on the discrete element method is proposed. The rock freeze-thaw process is simulated using a particle flow program, and the reliability of the simulation results is verified through laboratory experiments. The frost heave evaluation index of pore water particles is quantitatively characterized, and a functional relationship between and the number of freeze-thaw cycles N is established. Furthermore, the fracture characteristics and the evolution of microcrack, displacement field and force chain field in freeze-thawed rocks during the …


Study On The Identification Method Of Tunnel Surrounding Rock Failure Zone Based On Continuous Discontinuous Analysis Theory, Ming-Qing Xiao, Chen Xu, Jian Yang, Jia-Ming Wu, Xiao-Dong Fu, Yong-Qiang Zhou Feb 2024

Study On The Identification Method Of Tunnel Surrounding Rock Failure Zone Based On Continuous Discontinuous Analysis Theory, Ming-Qing Xiao, Chen Xu, Jian Yang, Jia-Ming Wu, Xiao-Dong Fu, Yong-Qiang Zhou

Rock and Soil Mechanics

Accurate analyzing the scope of tunnel excavation failure zone has important guidance and engineering significance in determining support parameters reasonably. This study focuses on the identification methods of tunnel surrounding rock failure zone, specifically the continuous medium analysis method and the continuous-discontinuous method represented by the finite element-discrete element coupling method (FDEM). Firstly, the continuous medium analysis method and FDEM identification criteria for surrounding rock failure are studied. Then the rock mass is divided into elastic rock elements and elastic-plastic interface elements. Based on the concept of equivalent continuous model, the relationship between the mechanical parameters of interface elements and …


Law Of Disturbed Stress Rotation Induced By Hard Rock Excavation And Its Influence On Rock Fracture, Qian-Cheng Sun, Yue Liu, Qing-Wen Wang, Shao-Jun Li, Min-Zong Zheng Feb 2024

Law Of Disturbed Stress Rotation Induced By Hard Rock Excavation And Its Influence On Rock Fracture, Qian-Cheng Sun, Yue Liu, Qing-Wen Wang, Shao-Jun Li, Min-Zong Zheng

Rock and Soil Mechanics

The rock fracture caused by disturbed stress field change in deep underground engineering is a common issue receiving continuous attention. After analyzing the test data of disturbed stress field in Jinping underground laboratory phase II project, the variation law of disturbed stress field under different construction processes was interpreted, and the change mode of principal stress direction was analyzed. Through the comparative analysis about in-situ drilling imaging of rock mass, the influence of principal stress direction change on surrounding rock fracture was revealed. The results show that the disturbed stress field changes the most actively at the stage of middle …


Thermo-Hydro-Mechanical Coupling Model For Natural Gas Hydrate-Bearing Sediments With Depressurization Based On Opengeosys, Zhi-Gang Ye, Lu-Jun Wang, Bin Zhu, Yun-Min Chen Feb 2024

Thermo-Hydro-Mechanical Coupling Model For Natural Gas Hydrate-Bearing Sediments With Depressurization Based On Opengeosys, Zhi-Gang Ye, Lu-Jun Wang, Bin Zhu, Yun-Min Chen

Rock and Soil Mechanics

Natural gas hydrates are considered as one of the most important potential alternatives for energy shortage, and depressurization is believed to be the most economic effectiveness for hydrate exploitation. The exploitation induces solid hydrate dissociation, liquid / gas generation and migration, heat transfer and skeleton deformation, showing strong thermo-hydro-mechanical (THM) coupling behavior of sediments. These processes will trigger geotechnical hazards, such as borehole inclination and reservoir collapse. A THM coupling numerical model for hydrate exploitation was developed based on the open-source FEM platform OpenGeoSys. In detail, the kinetic reaction equation was implemented to represent the liquid/gas generation during gas hydrate …


Analytical Solution Of Deformation Of Underlying Shield Tunnel Caused By Foundation Pit Excavation And Dewatering, Ling-Xiao Guan, Chang-Jie Xu, Xue-Peng Wang, Xue-Qin Xia, Wen-Hai Ke Feb 2024

Analytical Solution Of Deformation Of Underlying Shield Tunnel Caused By Foundation Pit Excavation And Dewatering, Ling-Xiao Guan, Chang-Jie Xu, Xue-Peng Wang, Xue-Qin Xia, Wen-Hai Ke

Rock and Soil Mechanics

The foundation pit excavation and dewatering break the equilibrium stress field of the surrounding soil layer and negatively affect the underlying shield tunnel. The analytical solution of the longitudinal deformation of the underlying tunnel caused by foundation pit excavation and dewatering is proposed using a two-stage analysis method. In the first stage, Mindlin elastic solution and effective stress principle are used to calculate the additional stress caused by excavation and dewatering. In the second stage, the shield tunnel is treated as a Timoshenko beam resting on the Pasternak foundation to simulate the interaction between the tunnel and soil. The analytical …


Bearing Capacity Of Shallow Foundations Considering Geological Uncertainty And Soil Spatial Variability, Qi-Hao Jiang, Jin-Tong Wang, Bo Hou, Dong-Ming Zhang, Jin-Zhang Zhang Feb 2024

Bearing Capacity Of Shallow Foundations Considering Geological Uncertainty And Soil Spatial Variability, Qi-Hao Jiang, Jin-Tong Wang, Bo Hou, Dong-Ming Zhang, Jin-Zhang Zhang

Rock and Soil Mechanics

The bearing capacity of shallow foundations is significantly affected by stratum uncertainty, mainly including geological uncertainty and spatial variability of soil properties. The influence of geological uncertainty and soil spatial variability on the bearing capacity of shallow foundations has been separately investigated in previous studies. This study aims to develop a general probabilistic computational framework to reveal the effects of geological uncertainty and spatial variability of soil properties on the bearing capacity of shallow foundations, in which the geological uncertainty is simulated by Markov random field and the soil spatial variability is characterized using log-normal random field in different strata …


Analysis Of Shear Characteristics Of Soil-Rock Mixture–Geotextile Interface Under Normal Cyclic Loading, Shui-Jiang Li, Jia-Min Yao, Fei-Yu Liu, Hong-Bo Liu, Juan Hou Feb 2024

Analysis Of Shear Characteristics Of Soil-Rock Mixture–Geotextile Interface Under Normal Cyclic Loading, Shui-Jiang Li, Jia-Min Yao, Fei-Yu Liu, Hong-Bo Liu, Juan Hou

Rock and Soil Mechanics

The dynamic shear characteristics of the reinforcement–soil interface affect the stability and durability of reinforced soil–rock mixture subgrades. A series of static and dynamic direct shear tests was conducted on the soil–rock mixture–geotextile interface using a large dynamic direct shear apparatus under different rock contents (0%, 25%, 50%, 75% and 100%). The effects of normal stress amplitude (10, 20, 30, 40 and 60 kPa) and normal loading frequency (0.5, 1.0 and 2.0 Hz) on the shear response of the interface were analyzed. The test results indicate that the shear strength of the upper and lower boundaries of the interface first …


Field Study On The Ultimate Bearing Capacity Of Enlarged Grout Base Of Pre-Bored Grouted Planted Pile, Wei-Dong Wang, Meng Wang, Jiang-Bin Wu Feb 2024

Field Study On The Ultimate Bearing Capacity Of Enlarged Grout Base Of Pre-Bored Grouted Planted Pile, Wei-Dong Wang, Meng Wang, Jiang-Bin Wu

Rock and Soil Mechanics

Pre-bored grouted planted pile is a new type of eco-friendly pile foundation. The combination of the lower section of PHC nodular pile and the pile base expansion greatly improves the vertical bearing capacity of single pile. A lot of application practices have been achieved in Jiangsu, Zhejiang and Shanghai regions, but limited to the current research status, the bearing capacity of enlarged grout base is not clear. Based on the in-situ self-balanced loading test, the ultimate compressive bearing capacity of the enlarged grout base of the pre-bored grouted planted pile is investigated. The research results reveal that the measured ultimate …


Meso-Structure Damage Evolution In Shear Bands Of Granite Residual Soil, Cheng-Sheng Li, Ling-Wei Kong, Rong-Jun Shu, Zhi-Jun Liu, Bing-Xin Zhang Feb 2024

Meso-Structure Damage Evolution In Shear Bands Of Granite Residual Soil, Cheng-Sheng Li, Ling-Wei Kong, Rong-Jun Shu, Zhi-Jun Liu, Bing-Xin Zhang

Rock and Soil Mechanics

Shear band and crack evolution are very important for landslides. Crack is the weakest area in soil, and there is a lack of effective methods to analyze the meso-structure damage in shear bands quantitatively. To reveal the influence of cracks in granite residual soil on shear deformation and failure, CT scanning was used to obtain volume images of the sample at different loading stages during triaxial loading. Based on the digital volume correlation (DVC) method, a crack classification method is established according to the connectivity characteristics of cracks before and after loading. The cracks can be divided into eight kinds: …


Performance Of Finned Pile Under Torsional Load In Sand, Aalaa Khater, Ahmad Nasr Prof, Waseim Azzam Prof Jan 2024

Performance Of Finned Pile Under Torsional Load In Sand, Aalaa Khater, Ahmad Nasr Prof, Waseim Azzam Prof

Journal of Engineering Research

The pile foundations can experience torsional loads from earthquakes, wind, waves, offshore wind turbines, electrical transmission towers, and ship collisions in the maritime environment. Additionally, the axial load from the supporting superstructures can also cause torsional loads. This paper presents a new approach to pile modification called the finned pile. To enhance the torsional capacity of a single pile in the sand (where sand was used in a state of medium density Dr=50%), with or without fins, a number of experimental tests were conducted to investigate the effects of torsional loads (T), these studies involved varying the length, width, shape, …