Geotechnical Engineering Commons^™

Multivariate Experimental Study On Soybean Urease Induced Calcium Carbonate Precipitation, Meng Cui, Xiao Fu, Jun-Jie Zheng, Su-Ying L, Hui-Hui Xiong, Chen Zeng, Shang-Yu Han

Rock and Soil Mechanics

The plant-derived enzyme induced calcium carbonate precipitation (EICP) can significantly improve the engineering mechanical properties of sand. However, there is no specification for choosing the parameter value in the specific operation, and the solidification effect needs to be improved. Based on soybean urease, the effects of temperature, urease concentration, urea concentration, calcium concentration, pH value, calcium source type and other variables on urease activity and calcium carbonate precipitation were studied, and the SEM and XRD tests on precipitated calcium carbonate crystals were carried out. On this basis, the unconfined compressive strength and solidification effect of soybean urease-solidified sand were tested. …

Laboratory Investigation On The Effect Of Waste Plastic Bottles Filled With Soil As Transverse Members On Pullout Resistance Of Steel Strip For Reinforcement Fine Sand, Beyranvand Alireza, Hamid Lajevardi Seyed, Ghazavi Mahmoud, Mohammad Mirhosseini Seyed

Rock and Soil Mechanics

The aim of this study is to investigate the feasibility of utilizing the waste plastic bottles filled with soil as the transverse element attached to the steel stripe in the Mechanically Stabilized Earth Walls (MSEWs). Transverse members of reinforcement have a major effect on increasing the pullout resistance. This system is comprised of a steel stripe as a longitudinal member and waste plastic bottles filled with soil as transverse members attached to it. To understand this, pullout tests were conducted on one steel strip and seven steel stripes with one to seven bottles. More than 18 laboratory large-scale pullout tests …

Strength And Damage Characteristics Of Tailings Filling Body With Different Particle Size Distributions, Ai-Bing Jin, Jie Wang, Shuai-Jun Chen, Hai Li

Rock and Soil Mechanics

To explore the influence of tailings particle size distribution on strength and damage characteristics of filling body, uniaxial compression, scanning electron microscopy, and digital image correlation (DIC) tests were carried out on the filling body composed of ultrafine tailings (median particle size D50=10.1 m), fine tailings (D50=37.1 m), and coarse tailings (D50=121.31 m), and the strength and microstructure characteristics were analyzed. Based on the cusp mutation theory, the damage identification index of the filling body was established using wavelet packet technology, and the damage characteristics of the filling body were quantitatively analyzed. The results reveal that the strength and elastic …

A New Method For Evaluating Rock Joint Roughness Based On Power Spectral Density, Chuan-Qing Zhang, Yu-Hang Guo, Jin-Shun Xu, Ning Liu, Qi-Ming Xie, Guo-Jian Cui, Hui Zhou

Rock and Soil Mechanics

To further improve accuracy and reliability of describing the roughness feature of the structural plane, and more comprehensively reflect influences of the morphological differences, the fluctuation of the profile was decomposed into three principal characteristics: amplitude, inclination, and curvature, which represent the change characteristics of height, angle, and bending of the profile. The data of the three characteristics were obtained by 10 standard profiles established by Barton. And the distribution curves of the three characteristics were analyzed. Then, the power spectral density (PSD), which can well describe the microscopic morphology, was used to analyze the spectral characteristics of amplitude, inclination …

Stability Analysis Of Shield Tunnel Face Considering Spatial Variability Of Hydraulic Parameters, Shuai Yuan, De-Wang Feng, Sen-Hao Zhang, Yun-Peng Xing, Zun-Qi Ke

Rock and Soil Mechanics

The shield method is commonly employed in the construction of urban subways, and the stability of the excavation surface is extremely important for the safety of tunnel construction. When constructing tunnels in submerged or water-rich strata, the seepage force is a key factor affecting the ultimate support force of excavation faces. Uncertainty of natural geotechnical material hydraulic parameters significantly impacts the seepage force near the face. Based on the classic limit analysis and the random field theory, the principle of effective stress in saturated soil is introduced, and the stochastic numerical limit analysis method considering the influence of pore water …

A Rapid Determination Method Of Hydraulic Conductivity In Full Suction Range, A-Qiang Liu, Xu Li, Yan Liu, Zhi-Yuan Zhang

Rock and Soil Mechanics

The hydraulic conductivity function of unsaturated soil spans several orders of magnitude. Traditional measurement methods often take several months, and it is difficult to measure the hydraulic conductivity in the full suction range. In order to realize the rapid measurement of hydraulic conductivity in the full suction range, the wetting front advancing method is combined with the instantaneous profile method (here referred to as the combined determination method) in this study. A self-developed soil column infiltration device was used to measure the hydraulic conductivity of Qinghai silty clay in the full suction range under different dry densities. The test results …

Soil Moisture And Geomorphologic Data For Use In Dynamic And Forecastable Landslide Hazard Analyses In Eastern Kentucky, Daniel M. Francis, L. Sebastian Bryson

Civil Engineering Research Data

These data are the geomorphologic and land information system-based soil moisture estimates from assimilation of NASA SMAP satellite-based observations and NOAH 3.6 Land Surface Model estimates over known landslides in Eastern Kentucky. Additionally Long Short-Term Memory Recurrent Neural Network and logistic regression machine learning codes, as well as an Application programming interface code are included. Finally, in-situ data from Eastern Kentucky is included.

Spatiotemporal Retrievals Of Soil Moisture And Geomorphologic Data For Landslide Sites In Eastern Kentucky, Lindsey Sebastian Bryson, Daniel M. Francis

Civil Engineering Research Data

These data are the soil texture, land information system-based soil moisture estimates from assimilation of NASA SMAP satellite-based observations and NOAH 3.6 Land Surface Model estimates, artificial neural network machine learning code, and in-situ soil moisture measurements.

Historical And Forecasted Kentucky Specific Slope Stability Analyses Using Remotely Retrieved Hydrologic And Geomorphologic Data, Daniel M. Francis

Theses and Dissertations--Civil Engineering

Hazard analyses of rainfall-induced landslides have typically been observed to experience a lack of inclusion of measurements of soil moisture within a given soil layer at a site of interest. Soil moisture is a hydromechanical variable capable of both strength gains and reductions within soil systems. However, in situ monitoring of soil moisture at every site of interest is an unfeasible goal. Therefore, spatiotemporal estimates of soil moisture that are representative of in-situ conditions are required for use in subsequent landslide hazard analyses.

This study brings together various techniques for the acquisition, modeling, and forecasting of spatiotemporal retrievals of soil …

Development And Testing Of A Low Mass Vibratory Lunar Compactor, Charles Carey

Dissertations, Master's Theses and Master's Reports

NASA and other agencies are working to return to the moon, with the Artemis Program [1]. As a part of this new effort, an emphasis is being placed on having a sustained presence, building lunar bases and other permanent structures. The development of such infrastructure will require the development of civil engineering structures, and site preparation becomes a necessity. The Planetary Surface Technology Development Laboratory is developing a low mass lunar compactor as part of an autonomous site preparation vehicle in partnership with Colorado School of Mines, funded by NASA’s 2021 Lunar Surface Technology Research grant. The low mass lunar …

Development Of Practical Assessment Techniques For Sinkhole Potential In Florida Based On Sinkhole Vulnerability Indices, Sylvia Pesha

UNF Graduate Theses and Dissertations

Sinkholes are natural geohazards prevalent in Florida's distinctive karst geology, posing risks to public safety, infrastructure, and groundwater integrity. Considering the increasing frequency of sinkhole occurrences in Florida due to land development in vulnerable soils, understanding the potential for sinkhole occurrence can aid in the identification of high-risk locations and inform effective mitigation strategies. Researchers have developed three point-based indices to be used when assessing the vulnerability a project site has to sinkhole formation based on the encountered subsurface conditions. Engineers have historically used an index based on the subsurface layer thicknesses, called the Raveling Index (RI). In recent years, …

New Online Approach For Real-Time Precise Point Positioning Gnss Processing, Maha Fekry Elrewiny, Fawzi H. Zarzoura, Mahmoud El-Mewafi

Mansoura Engineering Journal

Real-time precise point positioning (PPP) is a promising technique for accurate position services. The merging of many systems is intended to increase real-time PPP performance. With a rising number of available satellites and progressively increased quality of real-time accurate products of satellite clocks and orbits, Platforms such as CSRS-PPP, AUSPOS, Magic-GNSS, Trimble, and PPP-MANS are reshaping the landscape of embedded solutions in a variety of sectors. the performance of real-time PPP must be tested on a regular basis. This article examines the benefits and drawbacks of real-time PPP, emphasizing its potential for high accuracy, fast decision-making, and easy interaction with …

Design Aspects Of Deep Water Distribution Shafts, Navid Allahverdi, V. Nasr

Publications and Research

This paper covers aspects of planning and designing of deep shafts with reference to two water distribution shafts under construction in New York City. The new shafts will be sunk into soil and rock to a depth to connect to existing Queens-Brooklyn tunnel section of City Tunnel No. 3 (CT3). The inside diameter of the upper parts of both shafts is 14.9 meter. Artificial ground freezing is specified as preferred method of excavation support for the entire stretch in soil. Excavation in competent rock will be performed using drill and blast technique preceded by a pre-excavation grouting program. Membrane waterproofing …

Numerical Study Of Sediment Suspension Affected By Rigid Cylinders Under Unidirectional And Combined Wave-Current Flows, Sha Lou, Xiaolan Chen, Shengyu Zhou, Gangfeng Ma, Shuguang Liu, Larisa Dorzhievna Radnaeva, Elena Nikitina, Irina Viktorovna Fedorova

Civil & Environmental Engineering Faculty Publications

Sediment transport modeling for flows with cylinders is very challenging owing to the complicated flow–cylinder–sediment interactions, especially under the combined wave-current flows. In this paper, an improved formulation for incipient sediment suspension considering the effect of cylinder density (i.e., solid volume fraction) is employed to simulate the bottom sediment flux in the flow with cylinders. The proposed model is calibrated and validated using laboratory measurements under unidirectional and combined wave-current flows in previous studies. It is proved that the effects of cylinders on sediment suspension can be accounted for through a modified critical Shields number, and the proposed model is …

Editorial: Rock Physics Modeling And Well-Log Practice For Unconventional Reservoirs, Qiaomu Qi, Lidong Dai, Maxim Lebedev, Tobias Müller, Junfang Zhang

Research outputs 2022 to 2026

Unconventional resources with commercial interest in the world mainly include heavy oils, shales, coalbed methane and tight gas sands. The production and development of these resources have changed the supply pattern of global energy. Quantitative interpretation of geophysical data in the exploration, well logging and engineering development of the unconventional resources requires a comprehensive understanding of the physical properties of rocks and their relationships. The research of rock physics provides an interdisciplinary treatment of physical properties, whether it is highly related to geological, geophysical and geomechanical methodologies. The development of new rock physics methods is essential when integrating core, well-log, …

A New Volumetric Strain-Based Method For Determining The Crack Initiation Threshold Of Rocks Under Compression, Hao Li, Ruizhi Zhong, Leo Pel, David Smeulders, Zhenjiang You

Research outputs 2022 to 2026

The crack initiation stress threshold ( ci) is an essential parameter in the brittle failure process of rocks. In this paper, a volumetric strain response method (VSRM) is proposed to determine the σci based on two new concepts, i.e., the dilatancy resistance state index ( ci) and the maximum value of the dilatancy resistance state index difference (| ci|), which represent the state of dilatancy resistance of the rock and the shear sliding resistance capacity of the crack-like pores during the compressive period, respectively. The deviatoric stress corresponding to the maximum | ci| is taken as the ci . We …

Energy Dissipation In A Sand Damper Under Cyclic Loading, Ehab Sabi

Civil and Environmental Engineering Theses and Dissertations

Various seismic and wind engineering designs and retrofit strategies have been in development to meet structures' proper and safe operation during earthquake and wind excitation. One such method is the addition of fluid and particle dampers, such as sand dampers, in an effort to reduce excessive and dangerous displacements of structures. The present study implements the discrete element method (DEM) to assess the performance of a pressurized sand damper (PSD) and characterize the dissipated energy under cyclic loading. The idea of a PSD is to exploit the increase in shearing resistance of sand under external pressure and the associated ability …

Continuous Moisture Measurement During Pavement Foundation Construction: Laboratory Measurements, Isaac Esteban Zuniga

Open Access Theses & Dissertations

Moisture content directly affects all properties of subgrade materials. A rapid, continuous, and accurate technique to determine moisture content during subgrade construction is the next step needed to improve the mechanistic-based quality of pavement foundations. In this study, six geomaterials were compacted to standard/modified proctor specifications and subjected to laboratory measurements to study the variations in their electromagnetic and electric properties with moisture content. The relationships between the seismic modulus, unconfined compressive strength, lightweight deflectometer, and moisture content for the same geomaterials were also established. Large-scale replicate specimens were also compacted and subjected to numerous measurements. The dielectric constant measured …

Development Of An Excel Model To Evaluate The Stability Of Slopes, Bradley Davis

All Graduate Plan B and other Reports, Spring 1920 to Spring 2023

This objective of this study is to determine a method or tool for taking given slope stability parameters and quickly and effectively determining the factor of safety against sliding of fully softened slopes. This study evaluates the effects of soil and geometric parameters of common slopes, and models these properties in a hypothetical model. The methodology is based on a parametric analysis using the Spencer’s Method of Slices limit equilibrium analysis used in the computer program Slide2. A parametric analysis is performed to determine which soil and/or geometric properties have a high influence on slope stability. The parametric analysis is …

Investigation Of Geopolymer Based Soil Stabilization Methods For Expedient Airfield Pavement Surfaces, Brett Albertson

All Theses

The United States Air Force (USAF) has the unique capability of being able to interdict superior airpower anywhere, at any time. However, superior airpower is only as effective as the amount of time an aircraft can spend in a particular area. The closer an aircraft can get to the mission need, the more time that can be spent in the air, or the less time that must be spent moving in and out of the operational area. Through the use of skilled and experienced men and women, the USAF is able to apply expedient and unsurfaced airfield paving techniques that …