Engineering Commons^™

Analytical Method To Estimate The Influence Of Foundation Pit Excavation Adjacent To The Station (Working Shaft) On The Underlying Shield Tunnel, Zu-Xian Wang, Cheng-Hua Shi, Chen-Jie Gong, Cheng-Yong Cao, Jian-Wen Liu, Zhu Peng

Rock and Soil Mechanics

The shield tunnel is typically simplified as an infinite beam with two free ends in existing analytical models, which are used to calculate the longitudinal deformation of the underlying shield tunnel induced by the excavation of a foundation pit. However, the applicability of those analytical models is limited due to the simplification. The current study is aimed at estimating analytically the longitudinal deformation of the underlying shield tunnel induced by the excavation of a foundation pit adjacent to the station (working shaft). The constraint on the shield tunnel generated by the joint between the station (working shaft) and the tunnel …

Cascadia Subduction Zone Earthquake Vertical Ground Acceleration Investigation And Potential Impact On Bridges In The Pacific Northwest, Rachel Caroline Bassil

Civil and Environmental Engineering Master's Project Reports

The effects of vertical ground accelerations during subduction zone earthquakes currently are not sufficiently understood. There are numerous case studies and evidence that effects of vertical ground accelerations can significantly impact the performance of bridges during a seismic event, but most previous research has been focused on shallow crustal earthquakes. Current bridge design codes provide little guidance for accounting for vertical ground accelerations in seismic design, in part because additional information is needed about the characteristics of vertical ground motions during Cascadia Subduction Zone (CSZ) earthquakes in the Pacific Northwest.

For this study, recorded seismic data from recent subduction zone …

Progressive Failure Strength Characteristics Of Anisotropic Rocks Caused By Mineral Directional Arrangement: A Case Of Biotite Quartz Schist, Han Bao, Zhi-Yang Chen, Heng-Xing Lan, Run-Sheng Pei, Fa-Quan Wu, Chang-Gen Yan, Yue Tao

Rock and Soil Mechanics

To explore the strength characteristics of anisotropic rocks caused by mineral directional arrangement during progressive failure process, biotite quartz schist was taken as an example, and triaxial compression tests were carried out on samples with schistosity angles of 0°, 45° and 90°. The macro and micro failure characteristics and progressive failure strength index of the specimens were analyzed, and the differences with other types of anisotropic rock were discussed. The results show that the failure characteristics of biotite quartz schist are closely related to its schistosity. With the schistosity angle increasing from 0° to 90°, the main macro and micro …

Multi-Scale Analysis Of Damage Evolution Of Freezing-Thawing Red Sandstones, Hui-Mei Zhang, Yun-Fei Wang

Rock and Soil Mechanics

We take red sandstone as the research object and apply the freeze-thaw cycles, CT scans and mechanical properties experiments. We use image processing technology combined with genetic algorithm optimization model to achieve the denoise, enhancement, segmentation and three-dimensional reconstruction of CT scan images after 0, 5, 10, 20, and 40 freeze-thaw cycles. With the damage identification and comparative study of the same object across scales, we established a prediction formula of elastic modulus deterioration based on mesoscopic damage. Therefore, the macroscopic mechanical behavior of freeze-thaw red sandstones can be interpreted from the physical nature of the material meso-structure. The results …

Reliability Analysis Of Slope Under Rainfall Infiltration Considering Preferential Flow Model, Yun-Qi Yao, Run-Qiang Zeng, Jian-Hua Ma, Xiang-Pei Meng, Hong Wang, Zong-Lin Zhang, Xing-Min Meng

Rock and Soil Mechanics

Rainfall-induced landslides are the most common geological hazard in the world, and the effect of preferential flow infiltration has been neglected for a long time regarding the slope reliability analysis under rainfall infiltration. The preferential infiltration under rainfall conditions is solved numerically by Comsol Multiphysics, and the slope factor of safety is calculated using an infinite slope model. An improved Cholesky decomposition method is applied to generate spatially correlated random fields, and the slope reliability during rainfall is analyzed using the Monte Carlo method. Combining the deterministic and reliability results to compare the variation of slope factor of safety between …

Macroscopic And Microscopic Experimental Study On Fractal Fragmentation Characteristics Of Calcareous Sand During One-Dimensional Compression Creep, Bin Chen, Jian Deng, Jie-Ming Hu, Jian-Lin Zhang, Tao Zhang

Rock and Soil Mechanics

Calcareous sand is a natural foundation material for ports, airports and some civil buildings in ocean areas. Through the one-dimensional compression creep test of calcareous sand and the analysis of its micro-structure, it was found that the surface pore area decreased after creep and showed a dispersed distribution. In addition, the characteristics of instantaneous deformation, rapid deformation and attenuation deformation of the sample during the test were highly correlated with the particle size. The relative particle breakage rate and mass fractal dimension improved based on fractal theory were used to describe the degree of particle breakage after creep. The relationship …

Rapid Prediction Method Of Soil-Water Characteristic Curve Of Yan’An Compacted Loess, Hai-Man Wang, Wan-Kui Ni, Kui Liu

Rock and Soil Mechanics

The traditional SWCC test method is time-consuming, and it is of great practical significance to develop a method that can quickly determine the SWCC of unsaturated soil. In order to predict the SWCC of compacted loess rapidly, the water potential and moisture content of compacted loess with different dry densities were tested, and the pore size distribution curve was measured using nuclear magnetic resonance (NMR) technology. Based on the test results, a rapid prediction method of the soil-water characteristic curve of Yan’an compacted loess was established based on the void ratio, and its accuracy was verified by the measured data. …

Experimental Study On Crack Evolution And Damage Characteristics Of Water Bearing Sandstone Under Cyclic Loading, Ke Yang, Zhai-Nan Zhang, Xiao-Lou Chi, Xin L, Zhen Wei, Wen-Jie Liu

Rock and Soil Mechanics

Based on the engineering background that rock masses of underground reservoirs in mines are frequently disturbed by cyclic loads such as mine earthquake and mining stress, uniaxial compression and cyclic loading tests for sandstones with different water contents were carried out in laboratory. The crack propagation and failure laws of sandstones with different water contents were revealed by digital speckle technique. Based on scanning electron microscopic (SEM) analysis, the micro deterioration mechanism of sandstones with different water contents under cyclic loading was obtained. The test results show that the peak strength of sandstone decreases gradually with the increase of water …

Energy Evolution And Failure Characteristics Of Single Fissure Carbonaceous Shale Under Drying−Wetting Cycles, Xin-Xi Liu, Yu Li, Zi-Jian Fan, Sheng-Nan Li, Wei-Wei Wang, Peng Dong

Rock and Soil Mechanics

In order to investigate the energy evolution and failure characteristics of carbonaceous shale containing single fissure under drying−wetting cycles, the intact carbonaceous shale samples and the carbonaceous shale samples with fissure angles of 30°, 45° and 60° were prepared. MTS815 rock mechanics test system was used to conduct triaxial compression tests under different drying−wetting cycles. The influence of drying−wetting cycles on the strength, failure mode and energy evolution of single fissure carbonaceous shale were studied. The results show that the elastic energy and dissipated energy at crack initiation stress, damage stress and peak stress present exponential relationships with drying-wetting cycles. …

Stochastic Seismic Response Analysis Of Engineering Site Considering Correlations Of Critical Soil Dynamic Parameters, Zi-Lan Zhong, Yue-Bo Shi, Jin-Qiang Li, Mi Zhao, Xiu-Li Du

Rock and Soil Mechanics

This paper presents a method to generate random samples of soil dynamic shear modulus and dynamic damping curves with full consideration of the correlations of critical soil dynamic parameters to investigate the influence of their uncertainties on the engineering site seismic response in the implementation of equivalent linear method. A one-dimensional (1D) equivalent linear site seismic response analysis program, which serves stochastic dynamic response analysis of the engineering site, has been developed in MATLAB. A 1D free field model for the typical layered engineering sites of site class II is established in this study. The target response spectra, which are …

Mechanical Response Characteristics Of Lining Structure Of Pipeline Karst Tunnels In Water-Rich Areas, Hao-Bo Fan, Ding-Kun Zhou, Yong Liu, Yu-Xiang Song, Zheng-Guo Zhu, Yong-Quan Zhu, Xin-Qiang Gao, Jia-Qi Guo

Rock and Soil Mechanics

For the karst tunnel with pipeline cavities in the surrounding rock, it is very easy to accumulate high water pressure in the pipeline cavity due to the influences of heavy rainfall on the surface and groundwater, which will lead to lining cracking, water leakage, and water gushing diseases. To explore the influence of high water pressure on the lining structure, model tests of pipeline karst tunnels under high water pressure were carried out, and the internal force characteristics of tunnel lining under the influence of cavity position and water head height were studied. Based on the test findings, the numerical …

Buckling Failure Analysis And Numerical Manifold Method Simulation For Malvern Hills Slope, Qiu-Sheng Wang, Rui-Tao Zhang, Hong Zheng

Rock and Soil Mechanics

Based on the energy equilibrium, the computational formula of critical buckling length of multi-layer rock slope is derived. Considering interlayer and cross joints, the numerical manifold method is used to simulate the buckling evolution process of Malvern hills slope in New Zealand, and the theoretical calculation and numerical simulation results are compared with the field measured data. The results show that numerical manifold method can accurately simulate slope buckling failure process by preforming interlayer and cross joints. The process of slope buckling deformation and instability failure can be divided into interlayer dislocation-slight bending, slope toe traction-sharp uplift and accelerated sliding-landslide …

Post-Failure Analysis Of Landslides In Spatially Varying Soil Deposits Using Stochastic Material Point Method, Guo-Tao Ma, Mohammad Rezania, Mohaddeseh Mousavi Nezhad, Bu-Tao Shi

Rock and Soil Mechanics

This paper presents the probabilistic analysis of landslides in spatially variable soil deposits, modeled by a stochastic framework which integrates the random field theory with generalized interpolation material point method (GIMP). Random fields are simulated using Cholesky matrix decomposition (CMD) method and Latin hypercube sampling (LHS) method, which represent material properties discretized into sets of random soil shear strength variables with statistical properties. The approach is applied to landslides in clayey deposits under undrained conditions with random fields of undrained shear strength parameters, in order to quantify the uncertainties of post-failure behavior at different scales of fluctuation (SOF) and coefficients …

Minimizing Surface Run-Off, Improving Underground Water Recharging, And On-Site Rain Harvesting In The Kathmandu Valley, Ambika P. Adhikari, Keshav Bhattarai

Himalayan Research Papers Archive

Nepal's political institutions and administrative units were thoroughly restructured in 2015 with the promulgation of the new Constitution. Several rural areas were combined to meet the definition of urban threshold criteria to classify rural areas into urban categories. Accordingly, over 3,900 local political and administrative units were amalgamated into 753 units, of which, 293 units are classified as urban. Within these newly defined urban areas, many natural environments have been converted into impervious surfaces such as paved roads, sidewalks, and building roofs. These impervious surfaces have drastically increased the amount of surface run-offs-often termed as "urban floods"--under increasing precipitation caused …

Correlations Between Dynamic Probe Blow Count And Undrained Shear Strength For Peat At A Well-Characterised Raised Bog In Ireland, David Mchugh, Ciaran Reilly, Juan Pablo Osorio

Articles

Peat deposits are generally heterogeneous, with large variations over small areas. Peat has an extremely high water content, high compressibility and low shear strength. This presents a major issue in studying the geomechanical behavior of peat. For this study, field and laboratory tests were conducted to establish the undrained shear strength (s_u) of peat at a cutover industrial peatland in Ireland which had been extensively characterized in the past. The new field work included TRL-type Dynamic Cone Penetrometer, Mackintosh probe and field vane shear tests. A correlation was developed between the Mackintosh probe “M-value” blow count and the …

Development Of Deep Shear Wave Velocity Profiles And An Approach To Generate Site Signature Consistent Pseudo Shear Wave Velocity Profiles In The Mississippi Embayment, Ashraf Kamal Himel

Graduate Theses and Dissertations

This dissertation details the development of a surface wave method (SWM) technique to generate deep shear wave velocity profiles (VS profiles), applying this technique at 24 sites across the Mississippi embayment and developing an approach to generate pseudo site signature consistent VS profiles from velocity functions and fundamental frequency. In the presented SWM technique, active and passive source surface wave measurements are inverted along with fundamental frequency to develop a site signature consistent VS profile. Multiple transformation methods, including MSPAC, HRFK and FK are used to resolve experimental dispersion data from surface wave measurements. SWM VS profile at the Central …

Three-Dimensional Seismic Stability Of Inhomogeneous Soil Slopes Using Limit Analysis Method, Yu-Nong Li, Chang Liu, Li-Wei Wang

Rock and Soil Mechanics

Based on the upper bound limit analysis theorem, the three-dimensional seismic stability of inhomogeneous soil slopes is investigated using the pseudo-dynamic approach, and the explicit expression of the factor of safety is obtained by the gravity increase method (GIM). In addition, the genetic algorithm is used for optimization and the results are verified by comparing with other published data. Parametric studies are performed to investigate the effect of relevant parameters on the stability of slopes. The results indicate that for the slope with the given height, the increase of width-to-height ratio and slope angle, and the decrease of internal friction …

Development And Application Of Multifunctional Shear Test Apparatus For Rock Discontinuity Under Dynamic Disturbance Loading, Guo-Jian Cui, Chuan-Qing Zhang, Hui Zhou, Jing-Jing Lu, Yang Gao, Ming-Ming Hu, Da-Wei Hu

Rock and Soil Mechanics

Dynamic disturbance is an important influence factor that causes the sliding instability of rock discontinuity and then triggers strong dynamic geological disasters, such as earthquakes and rock bursts. In order to study the mechanical response and disaster-causing mechanism of rock discontinuity under dynamic disturbance loading, a multifunctional shear test apparatus for rock discontinuity under dynamic disturbance loading (DDST-1800) is independently developed. The test apparatus is composed of normal and shear loading units with quasi-static loading, various normal boundary conditions, dynamic disturbance loading with complex and wide-frequency waveform (0.5−50 Hz), and wide-range shear velocity loading (0.000 1−10 mm /s) functions, pendulum …

Vertical Vibration Response Of Rigid Strip Footings On A Viscoelastic Soil Layer Overlying Bedrock, Chang-Jie Zheng, Yu-Ze He, Xuan-Ming Ding, Lu-Bao Luan, Ye-Wei Chen

Rock and Soil Mechanics

Considering the influence of soil thickness, the vertical vibration response of rigid strip footings resting on viscoelastic soil is theoretically investigated. Based on the assumptions for footing and foundation with rigid bedrock boundary condition, employing the method of Fourier transform, this mixed-boundary value problem is expressed as a pair of dual integral equations, which are transformed to a set of linear equations by means of Jacobi orthogonal polynomials and solved numerically. The solution in this study is compared with the solution of elastic half-space in the literature to verify its rationality. The results demonstrate that the attenuation of ground waves …

Analysis Of One-Dimensional Nonlinear Consolidation Of Soft Soil Considering Time-Dependent Loading With Continuous Drainage Boundary, Si-Si Wu, Wen-Qiang Luo, Yin-Can Li, Wei-Jian Cui, Shuo Wang

Rock and Soil Mechanics

Soil tends to have nonlinear compression characteristics, and the consolidation laws of soil are different under different compression characteristics. Considering the nonlinear characteristics of soil, variable load and continuous drainage boundary conditions, a one-dimensional consolidation equation is established. Its solutions are obtained by using the unconditionally stable finite difference method and semi-analytical method, and the reliability of the two methods is verified by the degradation of continuous drainage boundary condition and the comparison of the two solutions. Based on the solution of finite difference method, the influences of interface parameter, load parameters and nonlinear parameter on soil consolidation are analyzed …

Shear Fracture Mechanical Properties And Acoustic Emission Characteristics Of Discontinuous Jointed Granite, Gang Wang, Lei-Bo Song, Xi-Qi Liu, Chun-Yan Bao, Man-Qing Lin, Guang-Jian Liu

Rock and Soil Mechanics

No abstract provided.

Dominant Partitioning Method Of Rock Mass Discontinuity Based On Dbscan Selective Clustering Ensemble, Hua-Jin Zhang, Shun-Chuan Wu, Long-Qiang Han

Rock and Soil Mechanics

For the problems existing in the traditional single discontinuity (structural plane) based clustering model, such as the risk of misclassification or omission and the inability to identify noise and isolated values, a dominant partitioning method of rock mass discontinuity based on selective clustering ensemble using density-based spatial clustering of applications with noise (DBSCAN) algorithm is proposed. Firstly, the spatial coordinate transformation is performed with the attitude of discontinuity, and the sine of the angle between the unit normal vectors is defined as similarity measurement. Then, a certain number of different base clusters are constructed based on the DBSCAN algorithm, with …

Seismic Analysis Of Cantilever Earth Retaining Walls Embedded In Dry Sand By Simplified Approaches And Finite Element Method, Edgar Ferro, Andrea Oss, Lucia Simeoni

Rock and Soil Mechanics

No abstract provided.

Evolution Of Deformation Field And Energy Of Organic-Rich Oil Shale Under Uniaxial Compression, Lu-Nan Wang, Chuan-Qi Tao, Xiao-Meng Yin, Jie Han, Lei Yang, Gan-Ping Zhang

Rock and Soil Mechanics

The nonuniform distribution of organic matter in oil shale strata results in different mechanical response and failure mechanism. Uniaxial compression test, digital image correlation method and infrared thermal imaging technology were used to study the deformation field, temperature field and energy evolution characteristics of oil shale during the whole loading process under different organic matter abundances, and to reveal the influence of organic matter abundance on mechanical properties and deformation and failure mechanism of oil shale. The results show that the stress-strain characteristics of oil shale present gradual attenuation as the organic matter abundance increases, while the ductility has improved …

Temporal Lidar Scanning In Quantifying Cumulative Rockfall Volume And Hazard Assessment: A Case Study At Southwestern Saudi Arabia, Abdullah A. Alotaibi, Norbert H. Maerz, Kenneth J. Boyko, Ahmed M. Youssef, Biswajeet Pradhan

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Rockfalls and unstable slopes pose a serious threat to people and property along roads/highways in the southwestern mountainous regions of Saudi Arabia. In this study, the application of terrestrial light detection and ranging (LiDAR) technology was applied aiming to propose a strategy to analyze and accurately depict the detection of rockfall changes, calculation of rockfall volume, and evaluate rockfall hazards along the Habs Road, Jazan Region, Saudi Arabia. A series of temporal LiDAR scans were acquired at three selected sites. Our results show that these three sites have different degrees of hazard due to their geological differences. The mean volume …

Compound Flooding In Convergent Estuaries: Insights From An Analytical Model, Ramin Familkhalili, Stefan Talke, David A. Jay

Civil & Environmental Engineering Faculty Publications

We investigate here the effects of geometric properties (channel depth and cross-sectional convergence length), storm surge characteristics, friction, and river flow on the spatial and temporal variability of compound flooding along an idealized, meso-tidal coastal-plain estuary. An analytical model is developed that includes exponentially convergent geometry, tidal forcing, constant river flow, and a representation of storm surge as a combination of two sinusoidal waves. Nonlinear bed friction is treated using Chebyshev polynomials and trigonometric functions, and a multi-segment approach is used to increase accuracy. Model results show that river discharge increases the damping of surge amplitudes in an estuary, while …

Permeability And Porosity Of Loose Granular Salt, Evan J. Babcock

Civil Engineering ETDs

In this study, permeability and porosity measurements are made and reported for loose granular salt from the Waste Isolation Pilot Plant (WIPP). Measurements are made on a particularly wide range of particle sizes of this salt in a permeameter constructed large enough to fit and represent mixtures containing salt particles up to 25.4 cm in size. Salt samples with different particle size distributions are constructed and tested at varying levels of consolidation due to induced vibrations. Permeability measurements are made at a varying range of porosities for a given sample. Measurements are also compared with a predictive model for permeability …

Shear Strength Deterioration Of Geopolymer Stabilized Loess Under Wet-Dry Cycles: Mechanisms And Prediction Model, Rui Chen, Xing Zhang, Ruo-Yu Hao, Wei-Xing Bao

Rock and Soil Mechanics

No abstract provided.

Catastrophe Prediction Of Compression-Induced Fracturing And Failure For A Tower- Shaped Unstable Rock Mass With Gentle Dip Angle, Fu-Chuan Zhou, Hong-Mei Tang, Lin-Feng Wang

Rock and Soil Mechanics

No abstract provided.

Determining The Mechanical Parameters Of Asteroid Rocks Using Nwa13618 Meteorites And Microscale Rock Mechanics Experiment, Xu-Hai Tang, Jing-Jing Xu, Yi-Heng Zhang, Qi He, Zheng-Zhi Wang, Guo-Ping Zhang, Quan-Sheng Liu

Rock and Soil Mechanics

In the future, the extraterrestrial human activities, such as resources exploitation and base construction beyond the Earth need the aid of geotechnical engineering technology. Currently, there are only two approaches for humans to obtain the rock samples beyond the Earth: sample-return activities by spacecraft and meteorite investigation. Meteorites are rare, expensive, small and arbitrary in shape, so it is difficult to process them into standard rock samples required by MTS and other traditional macroscale rock mechanical tests. In this paper, a novel technique for measuring mechanical property of small-size meteorites was developed based on microscale rock mechanics experiments (micro-RME) and …