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Engineering behaviors of reinforced gabion retaining wall based on laboratory test

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Journal of Central South University 2010年第6期17卷 1351-1356页

作者：林宇亮杨果林李昀赵炼恒 School of Civil and Architectural Engineering Ce ntral South University

In order to study the engineering behaviors of reinforced gabion retaining wall,laboratory model test was carried *** load and unload of five levels(0-50,0-100,0-50,0-200 and 0-250 kPa) were *** earth pressure,lateral earth pressure,deformation behaviors of reinforcements,potential failure surface and deformation behaviors of wall face were *** show that vertical earth pressure is less than theoretical value,the ratio of vertical earth pressure to theoretical value increases nearly linearly with increasing load,and the correlation coefficient of regression equation is 0.92 for the second layer and 0.79 for the fifth *** distribution of lateral earth pressure along the wall back is nonlinear and it is less than theoretical value especially when the load imposed at the top of retaining wall is ***,reinforced gabion retaining wall will be in great safety when current method is *** deformation behaviors of reinforcements both in the third layer and the fifth layer are single-peak distributions,and the position of the maximum strain is behind that determined by 0.3H(Here H refers to the height of retaining wall) method or Rankine *** deformation of wall face increases with increasing load,and the largest lateral deformation occurs in the fourth layer,which lead to a bulging in the middle of wall face.

关键词： reinforced gabion earth pressure deformation laboratory test

Statistical analysis of physico-mechanical parameters of sandstones occurring in orogenic settings

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Journal of Mountain Science 2024年第4期21卷 1388-1402页

作者： PAPPALARDO Giovanna CARBONE Serafina MONACO Carmelo ZOCCO Giordana MINEO Simone Dipartimento Di Scienze Biologiche Geologiche E AmbientaliUniversitàDegli Studi Di CataniaCorso Italia 5795129 CataniaItaly

In northeastern Sicily(Italy),sandstone rock masses widely crop out as cover deposits over crystalline terrains belonging to the orogenic *** being part of the same geological formation,these sandstones are characterized by highly different features in terms of texture and physico-mechanical *** poses a scientific question on the possibility of tracing these rocks to a single statistical model,which could be representative of their main engineering geological ***,it is worth investigating on the possible reasons of such differences,that should be searched either in the current geographical sandstone distribution or in the rock *** this study,sandstone samples were collected from different sites and were analyzed at both the hand and thin section *** sandstone types were recognized,characterized by a different ***,the laboratory characterization allowed estimating their main physico-mechanical and ultrasonic properties,such as porosity,density,mechanical strength,deformability,and ultrasonic *** rock mechanical strength proved linked to the rock compactness and to the presence of lithic fragments,while pores and a pseudo-matrix between grains represent weakening *** data were also statistically analyzed by grouping the specimens according to a geographical criterion,with respect to their sampling area,but no link was found between location and rock ***,with the aim of achieving mathematical laws that could be used to predict some rock properties from others,useful for practical purposes when dealing with such a high property variability,single and multiple regression analyses were carried *** show that the Uniaxial Compressive Strength,porosity,and P-wave velocity are the best predictors for a quick,indirect estimation of the main physico-mechanical *** methodological approach developed for this research can be taken as reference to study other world

关键词： Sandstone laboratory test Uniaxial Compressive Strength Porosity Rocks

Effect of Wheel Load on Wheel Vibration and Sound Radiation

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Chinese Journal of Mechanical Engineering 2015年第1期28卷 46-54页

作者： HAN Jian WANG Ruiqian WANG Di GUAN Qinghua ZHANG Yumei XIAO Xinbiao JIN Xuesong State Key laboratory of Traction Power Southwest Jiaotong University

The current researches of wheel vibration and sound radiation mainly focus on the low noise damped wheel. Compared with the traditional research, the relationship between the sound and wheel/rail contact is difficulty and worth studying. However, there are few studies on the effect of wheel load on wheel vibration and sound radiation. In this paper, laboratory test carried out in a semi-anechoic room investigates the effect of wheel load on wheel natural frequencies, damping ratios, wheel vibration and its sound radiation, The laboratory test results show that the vibration of the wheel and total sound radiation decrease significantly with the increase of the wheel load from 0 t to 1 t. The sound energy level of the wheel decreases by 3.7 dB. When the wheel load exceeds 1 t. the attenuation trend of the vibration and sound radiation of the wheel becomes slow. And the increase of the wheel load causes the growth of the wheel natural frequencies and the mode damping ratios. Based on the finite element method （FEM） and boundary element method （BEM）, a rolling noise prediction model is developed to calculate the influence of wheel load on the wheel vibration and sound radiation. In the calculation, the used wheel/rail excitation is the measured wheel/rail roughness. The calculated results show that the sound power level of the wheel decreases by about 0.4 dB when the wheel load increases by 0.5 t. The sound radiation of the wheel decreases slowly with wheel load increase, and this conclusion is verified by the field test. This research systematically studies the cffcct of wheel load on wheel vibration and sound radiation, gives the relationship between the sound and wheel/rail contact and analyzes the reasons, therefore, it provides a reference for further research.

关键词： wheel load vibration and sound radiation finite element method (FEM) boundary element method (BEM) laboratory test field test

Mechanical properties and reinforcement effect of jointed rock mass with pre-stressed bolt

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Journal of Central South University 2020年第12期27卷 3513-3530页

作者： YANG Wen-dong LUO Guang-yu BO Chun-jie WANG Ling Lü Xian-xian WANG Ying-nan WANG Xue-peng College of Pipeline and Civil Engineering China University of PetroleumQingdao 266580China

Pre-stressed bolt anchorage is the key technology for jointed rock masses in rock tunnelling,slope treatment and mining *** investigate the mechanical properties and reinforcement effect of jointed rock masses with pre-stressed bolts,in this study,uniaxial compression tests were conducted on specimens with different anchoring types and flaw inclination *** software was used to verify and supplement the laboratory *** laws of the uniaxial compressive strength(UCS)obtained from the numerical simulations and laboratory tests were *** results showed that under the same flaw angle,both the UCS and elastic modulus of the bolted specimens were improved compared with those of the specimens without bolts and the improvements increased with an increase in the bolt *** the same anchoring type,the UCS and elastic modulus of the jointed specimens increased with an increase in the flaw *** pre-stressed bolt could not only restrain the slip of the specimens along the flaw surface but also change the propagation mode of the secondary cracks and limit the initiation of *** addition,the plot contours of the maximum principal strain and the Tresca stress of the numerical models were influenced by the anchoring type,flaw angle,anchoring angle and bolt position.

关键词： jointed rock mass pre-stressed bolt laboratory test numerical simulation

Numerical and experimental analyses of methane leakage in shield tunnel

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Frontiers of Structural and Civil Engineering 2023年第7期17卷 1011-1020页

作者： Jie HE Hehua ZHU Xiangyang WEI Rui JIN Yaji JIAO Mei YIN College of Civil Engineering Tongji UniversityShanghai 200092China State Key laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Key laboratory of Geotechnical and Underground Engineering of Ministry of Education Tongji UniversityShanghai 200092China d Department of Civil and Environmental EngineeringBrunel UniversityLondon UB83PHUK

Tunnels constructed in gas-bearing strata are affected by the potential leakage of harmful gases,such as methane *** on the basic principles of computational fluid dynamics,a numerical analysis was performed to simulate the ventilation and diffusion of harmful gases in a shield tunnel,and the effect of ventilation airflow speed on the diffusion of harmful gases was *** the airflow speed increased from 1.8 to 5.4 m/s,the methane emission was diluted,and the methane accumulation was only observed in the area near the methane leakage *** influence of increased ventilation airflow velocity was dominant for the ventilation modes with two and four *** addition,laboratory tests on methane leakage through segment joints were *** results show that the leakage process can be divided into“rapid leakage”and“slight leakage”,depending on the leakage pressure and the state of joint *** on the numerical and experimental analysis results,a relationship between the safety level and the joint deformation is established,which can be used as guidelines for maintaining utility tunnels.

关键词： shield tunnel harmful gas leakage numerical analysis laboratory test

Multi-objective optimization and experiment of nylon cord rubber in expandable packer

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Petroleum Science 2021年第1期18卷 269-284页

作者： Yan-Wen Zhang Han-Xiang Wang Jia-Qi Che Ming-Chao Du Hong-Jie Zhang College of Mechanical and Electronic Engineering China University of Petroleum(East China)Qingdao 266580ShandongChina

Nylon cord rubber has the advantages of small residual deformation and is easy to lift and lower the tubing string in low-permeability oil and gas ***,it is associated with low-pressure resistance and poor sealing *** enhance the performance of nylon cord rubber,a three-dimensional numerical model of the nylon cord rubber was established and its accuracy experimentally *** Plackett-Burman test,the Steepest climbing test and the Response surface method were used to acquire the polynomial response surface model connecting structural parameters with bearing and sealing *** genetic algorithms,optimal structural parameters of nylon cord rubber were determined depending on field *** reliability of the optimized results was verified by laboratory *** was shown that after optimization,the bearing capacity of the expandable packer increased by 25%while the sealing performance increased by 66%.In addition,the bearing pressure was 70 MPa while the sealing pressure was 50 *** measurements effectively met the on-site requirements of high-pressure and fine fracturing in low-permeability oil and gas reservoirs.

关键词： Low-permeability reservoirs Nylon cord rubber Numerical simulation Response surface method Multi-objective genetic algorithm laboratory test

Effects of pre-existing cracks and infillings on strength of natural rocks--Cases of sandstone, argillite and basalt

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Journal of Rock Mechanics and Geotechnical Engineering 2020年第6期12卷 1333-1338页

作者： Chen Cui Ivan Gratchev School of Engineering Griffith UniversityGold CoastAustralia

This study aims to examine the influence of pre-existing discontinuities on the strengths of four natural rocks of different origins.A series of unconfined compression tests was performed on specimens of two types of sandstones,argillite and basalt that contain open and filled *** was found that the presence of cracks tends to decrease the overall strength for all studied rocks;however,the magnitude of strength reduction is related to the property of *** larger strength decrease was observed for the relatively harder argillite and basalt,compared to the softer *** was also found that the infill material could increase the strength of rock specimens,while the obtained strength depended on the characteristics of the fill material.

关键词： Pre-existing crack Rock strength Infill material laboratory test

Geotechnical behavior of the MSW in Tianziling landfill

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Journal of Zhejiang University Science 2003年第3期4卷 324-330页

作者：朱向荣金建明方鹏飞 NingboInstituteofTechnology ZhejiangUniversityNingbo315104China CollegeofCivilEngineeringandArchitecture ZhejiangUniversityHangzhou310027China

The valley shaped Tianziling landfill of Hangzhou in China built in 1991 to dispose of municipal solid waste (MSW) was designed for a service life of 13 years. The problem of waste landfill slope stability and expansion must be considered from the geotechnical engineering point of view, for which purpose, it is necessary to understand the geotechnical properties of the MSW in the landfill, some of whose physical properties were measured by common geotechnical tests, such as those on unit weight, water content, organic matter content, specific gravity, coefficient of permeability, compressibility, etc. The mechanical properties were studied by direct shear test, triaxial compression test, and static and dynamic penetration tests. Some strength parameters for engineering analysis were obtained.

关键词： Municipal solid waste (MSW) Engineering properties laboratory test In situ test

A laboratory study of stress arching around an inclusion due to pore pressure changes

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第4期10卷 678-693页

作者： Hani Asaei Mahdi Moosavi Mohammad Ali Aghighi University of Tehran TehranIran

When the pore pressure in a porous rock changes, stress arching will occur within the rock and the surrounding region. Stress arching ratio is defined as the total stress changes in the porous rock to the pore pressure change in the region. The region may have the same or different elastic moduli with the surrounding rock, which is usually referred to as inclusion or inhomogeneity. Stress arching is responsible for many geomechanical problems encountered during production or injection; in addition, it is a crucial parameter in stress estimation during field development. This paper aims to present laboratory measurements of vertical stress arching ratio in a material surrounding the inclusion(inhomogeneity).To the authors’ knowledge, few laboratory experiments have been reported on direct measurement of stress arching. The inclusion is a cylindrical sandstone(44 mm in diameter and 50 mm in height)embedded in a larger cylindrical sandstone(150 mm in diameter and 154 mm in height), both of which are made synthetically. These two parts are separated and sealed by a internal polyurethane *** stress changes are recorded by a mini hydraulic sensor embedded in surrounding rock. laboratory results are compared to those obtained by numerical models. These models are checked with analytical formulations. The results of numerical models show a good agreement with laboratory *** numerical results also indicate that the sensor response is affected by elastic properties of the internal sleeve. According to the sensitivity analysis performed, in the absence of the internal sleeve,properties of the inclusion have significant effects on the surrounding stress arching induced.

关键词： Stress arching laboratory test Large-scale sample Synthetic sandstone