PROPOSAL OF THERMOPHYSICAL PROPERTIES EVALUATION METHOD OF BEDROCK BY IN-SITU TEST AND NUMERICAL ANALYSIS USING CHARACTERISTICS OF UNDERGROUND SPACE IN OYA AREA

2020 ◽  
Vol 76 (5) ◽  
pp. I_289-I_299
Author(s):  
Shun SHIMOYAMA ◽  
Akira TOMIGASHI ◽  
Daichi SATO ◽  
Shohei KANEKO ◽  
Rei SATO ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Thermophysical Properties ◽  
Evaluation Method ◽  
Underground Space ◽  
In Situ Test

Comparative and Study the Influence of Sand Depth for Liquefied Evaluation

2013 ◽  
Vol 842 ◽  
pp. 733-736
Author(s):  
Zhao Yan Li ◽  
Zhuo Shi Chen
Keyword(s):  
Field Data ◽  
Evaluation Method ◽  
Evaluation Methods ◽  
Critical Curve ◽  
National Standard ◽  
Tangshan Earthquake ◽  
In Situ Test ◽  
Test Technology ◽  
At Home

CPT is a kind of relatively superior field test technology, which is one of important the liquefaction in-situ test at home and abroad. In 1987, China has formed the national standard CPT liquefaction evaluation method, which predominantly from 1976 Tangshan earthquake liquefaction data, and then has not been tested. Recently by the 40 CPT liquefaction field data of Bachu earthquake obtained a liquefied evaluation formula. Due to comparing the liquefied evaluation methods at home and abroad, found the national standard CPT liquefied critical curve is qualitatively distinct to the others liquefied evaluation methods. If it is wrong about the code of CPT liquefied evaluation method, which the liquefied critical curve will be smaller along with the direction of the depth, will direct the liquefied evaluation critically be conservative and the depth liquefaction evaluation clearly be hazardous. In theory, this problem can be attributed to the influence of sand depth for liquefied evaluation, worthy of further discussion.

Numerical Analysis of Tension Force Subjected by Flexible Mattress

2015 ◽  
Vol 740 ◽  
pp. 116-119
Author(s):  
Zhen Yu Li ◽  
Ping Yang ◽  
Zhi Hua Sun ◽  
Lin Suan Liu
Keyword(s):  
Numerical Analysis ◽  
Large Strain ◽  
Fem Analysis ◽  
Tension Force ◽  
Stress And Strain ◽  
Nonlinear Fem ◽  
Fem Model ◽  
In Situ Test ◽  
Distribution Of Stress

The nonlinear FEM analysis is performed to the problem of large strain nonlinear application for flexible mattress. The element with cloth type option is used to establish the FEM model for the analysis of flexible mattress. The simulation can produce correct profile of deformation, accurate distribution of stress and strain, meanwhile taking account of geometric nonlinear from large strain. The results of the paper are compared with those from the theory and in-situ test. Some valuable conclusions are made from the results analysis.

scholarly journals Design and Application of an In Situ Test Device for Rheological Characteristic Measurements of Liquefied Submarine Sediments

2021 ◽  
Vol 9 (6) ◽  
pp. 639
Author(s):  
Hong Zhang ◽  
Xiaolei Liu ◽  
Anduo Chen ◽  
Weijia Li ◽  
Yang Lu ◽  
...  
Keyword(s):  
Yellow River ◽  
Rheological Characteristic ◽  
Yellow River Delta ◽  
Turbidity Currents ◽  
Rheological Characteristics ◽  
Submarine Landslides ◽  
Test Device ◽  
Offshore Area ◽  
In Situ Test

Liquefied submarine sediments can easily lead to submarine landslides and turbidity currents, and cause serious damage to offshore engineering facilities. Understanding the rheological characteristics of liquefied sediments is critical for improving our knowledge of the prevention of submarine geo-hazards and the evolution of submarine topography. In this study, an in situ test device was developed to measure the rheological properties of liquefied sediments. The test principle is the shear column theory. The device was tested in the subaqueous Yellow River delta, and the test results indicated that liquefied sediments can be regarded as “non-Newtonian fluids with shear thinning characteristics”. Furthermore, a laboratory rheological test was conducted as a contrast experiment to qualitatively verify the accuracy of the in situ test data. Through the comparison of experiments, it was proved that the use of the in situ device in this paper is suitable and reliable for the measurement of the rheological characteristics of liquefied submarine sediments. Considering the fact that liquefaction may occur in deeper water (>5 m), a work pattern for the device in the offshore area is given. This novel device provides a new way to test the undrained shear strength of liquefied sediments in submarine engineering.

scholarly journals In Situ Shear Test for Revealing the Mechanical Properties of the Gravelly Slip Zone Soil

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6531 ◽  
Author(s):  
Zongxing Zou ◽  
Qi Zhang ◽  
Chengren Xiong ◽  
Huiming Tang ◽  
Lei Fan ◽  
...  
Keyword(s):  
Mechanical Property ◽  
Plastic Deformation ◽  
Shear Test ◽  
Slip Zone ◽  
Three Gorges Reservoir Area ◽  
Silty Clay ◽  
Sigmoid Function ◽  
In Situ Test ◽  
Deformation Stage

Slip zone soil is usually composed of clay or silty clay; in some special geological environments, it contains gravels, which make the properties of the slip zone soil more complex. Unfortunately, in many indoor shear tests, gravels are removed to meet the demands of apparatus size, and the in situ mechanical property of the gravelly slip zone soil is rarely studied. In this study, the shear mechanical property of the gravelly slip zone soil of Huangtupo landslide in the Three Gorges Reservoir area of China was investigated by the in situ shear test. The test results show that the shear deformation process of the gravelly slip zone soil includes an elastic deformation stage, elastic–plastic deformation stage, and plastic deformation stage. Four functions were introduced to express the shear constitutive model of the gravelly slip zone soil, and the asymmetric sigmoid function was demonstrated to be the optimum one to describe the relationship of the shear stress and shear displacement with a correlation coefficient of 0.986. The comparison between the in situ test and indoor direct shear test indicates that gravels increase the strength of the slip zone soil. Therefore, the shear strength parameters of the gravelly slip zone soil obtained by the in situ test are more preferable for evaluating the stability of the landslide and designing the anti-slide structures.

Coupled Thermo-Hydro-Geochemical Models of Engineered Barrier Systems: The Febex Project

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Numerical Models ◽  
Full Scale ◽  
Small Scale ◽  
Model Parameters ◽  
In Situ Test ◽  
Wide Range ◽  
Engineered Barrier

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

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