Geotechnical Engineering Commons^™

Study On The Mechanism Of Coal Bursts Induced By Quasi-Resonance Of Roof-Support System, Kai-Xing Wang, Jia-Qi Xue, Yi-Shan Pan, Lin-Ming Dou, Yong-Hui Xiao

Rock and Soil Mechanics

The mechanism and prevention of coal burst is an important issue in the study of coal mine dynamic disasters. The disturbance of surrounding rocks can trigger the quasi-resonance phenomena of roadway roof support system in close proximity to its resonant state, ultimately inducing impact disasters. This is manifested in three strong quasi-resonant responses, including roof displacement, velocity and acceleration. Based on the support instability and plastic buckling criteria, three safety factors and the corresponding dangerous disturbance frequency ratio interval for the dynamic failure of support are proposed, and the support damping control strategy is given, aiming at the impact disasters …

Centrifugal Experimental Study On Seismic Response Of Bridge Pile Group Foundation In Saturated Sand Field Overlain By Water, Zhi-Xiao Yan, Yu-Run Li, Dong-Sheng Wang, Yong-Zhi Wang

Rock and Soil Mechanics

In order to explore the dynamic interaction of the soil−pile group foundation−bridge structure system in saturated sand field overlain by water, a physical similarity model of the vertical (inclined) pile group foundation−bridge structure was designed and manufactured. Centrifuge shaking table tests with seismic wave inputs of different ground motion intensities and characteristics were conducted. The dynamic characteristic indices of pile group foundation−bridge structure were analyzed, and the development of excess pore water pressure in the saturated sand foundation overlain by water and the dynamic response of pile−soil interaction were also investigated. The results indicated that the presence of overlying water …

Relationship Between Macro And Micro Friction Coefficients Of Sandstone Structural Surface Based On Nano-Scratch Test, Shuang Zheng, Rui Yong, Shi-Gui Du, Zhi-Hai He, Zhen Zhong, Ying-Ying Zhang, Su-Gang Sui

Rock and Soil Mechanics

Basic friction coefficients are important parameters affecting the shear strength of structural surface in rock masses. The basic friction coefficient determined by conventional laboratory test methods is influenced by mineral composition, temperature, and other factors. To systematically reveal the basic frictional properties of structural surfaces, the macro and micro friction coefficients of sandstone were investigated separately, and their relationship was established. First, mineral components and mechanical parameters of the sandstone were determined by X-ray diffraction and nanoindentation tests. Second, the friction coefficient in the macro scale was examined by tilt test and direct shear test, and the direct shear test …

Numerical Study On Failure Path Of Rock Slope Induced By Multi-Stage Excavation Unloading Based On Crack Propagation, Chuan Wang, Xian-Lun Leng, Zhan-Rong Zhang, Chuang Yang, Jian Chen

Rock and Soil Mechanics

The investigation on failure patterns and paths of cracked rock slopes under excavation unloading is one of the hot issues in the slope engineering field. Accurate identification of the potential failure path is of great significance for excavation safety and support design of the slope. A theoretical method for crack propagation discrimination was embedded into the numerical simulation based on the fracture propagation analysis method, and the quick simulation of initiation, propagation, and coalescence of discontinuous cracks in rock masses was realized through stress intensity factor calculation at crack tip, crack propagation pattern recognition, crack initiation angle derivation, and crack …

An Improved Shear Strength Model Of Unsaturated Soils Over A Wide Suction Range, Yu-Xin Zhao, Xu Li, Sen Lin, Xiao-Meng Wang

Rock and Soil Mechanics

Different types of unsaturated soils are widespread in nature. Due to the differences in grain size and mineral composition, the shear strength characteristics of the unsaturated soils are significantly different over a wide suction range. In order to establish a unified model for predicting the shear strength of different soil types over a wide suction range, a systematic investigation was carried out to examine the effect of soil type on the shear strength of unsaturated soils. An improved shear strength model is proposed based on the advantages of two traditional equations. The proposed model is verified by comparing the published …

Effects Of Cut Depth And Cut Spacing On A Conical Pick In Rock Cutting, Jiu-Bo Liao, Xi-Bing Li, Shao-Feng Wang, Kun Du

Rock and Soil Mechanics

In order to study the effects of different cut depths and cut spacings on cutting force and specific cutting energy acting on a conical pick, the laboratory linear rock cutting tests were carried out on carbonaceous slate and rhyolite clastic rock based on the TRW-300 true triaxial electro-hydraulic servo system and self-designed innovative pick loading platform. Experimental results indicate that there were four types of failure modes on a conical pick in rock cutting, and there was a synergistic effect between two adjacent picks. The mean cutting force linearly increases with the increasing cut depth and cut spacing. The specific …

Penetration Resistance Evolution Characteristics And Mesoscopic Mechanism Of Submarine Pipeline In Sandy Seabed, Yang Yang, Ying-Hui Tian, Chun-Hui Zhang, Rong Wang, Zhi-Chao Wang, Le Wang

Rock and Soil Mechanics

Understanding the vertical penetration process of submarine pipelines is of fundamental significance for the reasonable assessment of the initial pipeline embedment during installation and safety and stability during service. Geotechnical centrifuge model tests, combined with discrete element method modelling were conducted to investigate penetration resistance evolution characteristics and mesoscopic mechanism of submarine pipeline in sand with different densities under the real stress level. The test results show that for the medium-dense sand, the pipe penetration resistance−embedment curve shows a hardening trend. On the other hand, for the dense sand, the pipe penetration resistance−embedment curve exhibits a periodic softening trend; moreover, …

Seepage Characteristics And Mechanical Response Of Shield Tunnels Under Localized Leakage And Exosmosis, Jia-Chong Xie, Xin Huang, Guo-Long Jin, Zi-Xin Zhang

Rock and Soil Mechanics

In order to address the problem of groundwater infiltration and inner water exosmosis induced by the hydraulic deterioration of lining joints in pressurized shield tunnels, the seepage characteristics and mechanical responses of tunnel lining and surrounding stratum under localized leakage conditions are analyzed through both numerical and analytical methods based on the hydraulic aperture theory. The results show that the analytical solutions derived from the classical image method for a multi-point leakage case match well with the numerical solutions, which verifies the effectiveness of the proposed numerical model of localized leakage. There is a significant difference in the characteristics of …

Three-Dimensional Analysis And Inclinometer Measurements In Deep Circular Excavation In Sand Soil, Hermil Rizki Hanifah, Paulus Pramono Rahardjo, Aswin Lim

Rock and Soil Mechanics

This paper presents the results of the inclinometer monitoring and back analysis using three-dimensional finite elements in the scale pit deep excavations. Scale pit is a deep circular excavation construction with a depth of −27 m and a total diameter of 26 m. The soil layer above from the final excavation is dominated by a sandy soil layer. The retaining wall construction is a secant pile reinforced with waler beams at each excavation stage. The hardening soil model was used as soil constitutive model. The results of the back analysis show that the trend of wall deflection is close to …

Numerical Study On Seismic Behavior Of Shield Tunnel Crossing Saturated Sandy Strata With Different Densities, Hong Wu, Zhi Ye, Yu-Ting Zhang, Hua-Bei Liu

Rock and Soil Mechanics

Earthquake-induced liquefaction poses a significant threat to underground structures. Particularly, tunnel structures located at the interface of different liquefaction-resistant strata are more prone to severe seismic damages. In this paper, a three-dimensional numerical study was carried out to investigate the seismic response of a shield tunnel passing through saturated sandy strata with different densities. Firstly, a boundary interface model that describes the liquefaction behavior of sand with different densities was used to simulate saturated sand, which was validated by shaking table experiments on a tunnel embedded in liquefiable soil. Secondly, a multi-degree- of-freedom link spring is applied to characterize the …

A High-Speed Portable Ground Heat Exchanger Model For Use In Various Energy Simulation Software, Ryan Davies, Matt Mitchell, Edwin Lee

Macalester Journal of Physics and Astronomy

A portable component model (PCM) of a ground source heat pump system was developed and used as a test case in the creating of a PCM development framework. By developing this framework, new building energy simulation models will be able to be easily integrated into existing simulation software such as EnergyPlus and the Modelica Buildings Library. Our model uses a time responsive g-function and numerical methods to simulate ground source heat pumps for single time steps as well as long time scales. We validated our model against GHESim and GLHEPro and found that our model agrees with these two standards …

Columbus, Nebraska: Southern Housing Development Design Proposal, Ryan Weyers, Caiden Dynek, Alex Papa, Brexton Robertson, Kaden Perala

Honors Theses

The following paper proposes the design and creation of a new housing development in the city of Columbus, Nebraska in a lot to the south of the city and directly north of the Columbus wastewater treatment plant. The goal of this proposal is to provide readers with confidence that our company is the most qualified to complete the project and will create the safest, most comfortable, most efficient, and most cost-effective final design. This proposal seeks to offer a solution to the lack of affordable housing for the growing workforce in Columbus. In order to arrive at this solution, each …

Evaluation Of The Geotechnical And Foundation Components On Jud Site, Mirabel W. Nkanor

Honors Theses

This thesis is part of the senior design final project of the Civil Engineering Department at the University of Mississippi. Geotechnical and foundation analyses were done on a proposed construction project for a multi-family home in Orlando, Florida. This evaluation done in this thesis follows the pre-existing geotechnical report on the side, USDA soil reports, ASCE Code 32-01 (Design of Foundations), and ASCE-7 Section 12.31.1 (Foundations and Superstructure-to-Foundation Connections).

A structural system was selected from the proposed location, on the corner of South Conway and Judge Road, and an evaluation of the Bearing Load capacity was completed to determine the …

Performance Of Helical Piles Retrofitted With A Novel Collar Vane Under Lateral And Torsional Loads, Juan Sebastian Carvajal Munoz

Electronic Theses and Dissertations

Helical piles are lightweight deep foundations designed to support both compressive and uplift loads by mobilizing the shear strength of soil adjacent to helical plates that are welded to an extendable shaft. Helical piles are relatively inexpensive, can be installed quickly utilizing non-specialized equipment, and they are suitable for a wide range of soil conditions. However, helical piles are precluded from many applications due to their inability to support substantial lateral and torsional loads. To overcome this limitation, a novel easy-to-install Collar Vane is implemented to augment the lateral and torsional capacity of helical piles.

The Collar Vane consists of …

Floating Offshore Wind Turbine Project, Courtney Huitt, Cormack Williams

Civil and Environmental Engineering

Offshore wind is a developing industry in the Central Coast with the advent of the future offshore wind project planned off the north coast of San Luis Obispo County. This senior design project aligns with the recently leased wind energy project as a detailed study on the structural design, geotechnical design, and construction of a single 14 MW floating offshore wind turbine (FOWT) located 40 km NW of Morro Bay (NOAA buoy 46028). A preliminary design of a spar FOWT is presented in this project as a solution to the rapidly increasing water depth off the coast of Morro Bay, …

Investigation Of Micp Based 3d Printed Soils, Kathleen Weston

Civil Engineering Undergraduate Honors Theses

The advent of additive manufacturing, often called 3D printing, offers potential for new and more sustainable soil improvement techniques. Previous research at the University of Arkansas has examined Microbially Induced Calcite Precipitation (MICP) as a possible binder option that is a more sustainable alternative to Portland cement and can be used in remote areas where Portland cement may not be available. The objective of this research is to develop an increased understanding of the potential of utilizing MICP as a spray binding technique for applications in 3D printed soils. The specific goals of this research include: examining the effectiveness of …

Behavior Analysis Of Cement Concrete With Combination Of Waste Rubber And Glass, Abdulaziz Alebra

Symposium of Student Scholars

Glass and Rubber waste materials are valuable materials to use rather than throw which we have more than enough to use and recycle. Recycled glass and rubber materials can reduce and help major climate issues in our times based on the statistics reducing glass can bring down air pollution by 20% and also reduce water pollution by 50% as well as can reduce the use of landfill space. A laboratory study will be launched, and tests will be conducted following the ASTM standards, ASTM C143 for a concrete slump, and ASTM C31 for making and curing concrete specimens. Samples of …

Laboratory Evaluation Of The Geotechnical Properties Of Biochar-Amended Clay, Brett Natelborg

Senior Honors Theses

The upkeep and rehabilitation of infrastructure damage related to the shrinking and swelling of expansive soils have cost the United States billions of dollars. Biochar, an innovative and eco-friendly additive proven to improve soil permeability, nutrient retention, and mechanical properties, is investigated as an additive to Mississippi chalk. The index properties of the chalk were determined and used to characterize its nature. The geotechnical engineering properties of the chalk amended with 6% and 12% biochar were evaluated via the Proctor compaction, compression, and direct shear tests. Results were analyzed to make comparative remarks on how the behavior of the chalk …

Effects Of Lead Contamination On Macro-Water Retention And Micro-Structural Evolution Of Loess, Shao-Jie Wen, Wen-Chieh Cheng, Wen-Le Hu

Rock and Soil Mechanics

The physical and chemical reactions between heavy metals in landfill leachate and soil may change the microstructure of soil, then the diffusion and migration of heavy metals and other toxic substances, threaten human health and surrounding environment. In order to investigate the effects of heavy metal contamination on macroscopic water retention and microstructure of loess, the soil-water characteristic curves of Pb-contaminated loess were measured by axial translation technique. Characterization of mesoscopic structure changes was clarified by scanning electron microscopy (SEM), mercury injection (MIP), X-ray diffraction (XRD) and Zeta potential. The results show that the air-entry values of Pb-contaminated loess decrease …

Model Test And Finite Beam Element Solution Of Cyclic Lateral Characteristics Of Piles In Sloping Ground, Wen-Zhe Peng, Ming-Hua Zhao, Chao-Wei Yang, Heng Zhao

Rock and Soil Mechanics

To reveal the cyclic lateral characteristics of piles in sloping ground under the combined influence of slope effect and cyclic weakening effect, one-way cyclic lateral loading tests with different cycle numbers, load amplitudes and slope angles were carried out, and corresponding lateral static loading tests were conducted as a comparison. The variation trends of pile head deflection, bending moment and subgrade reaction were revealed. Then, the element stiffness matrix was improved by considering the second-order effect and pile-soil interaction to develop the finite beam element solution. Finally, the theoretical predicted curves were compared with measured curves and results calculated by …