Influence of Cavity above Tunnel on Stratum Deformation and Failure in Urban Tunnelling

2012 ◽  
Vol 170-173 ◽  
pp. 1810-1815
Author(s):  
Yanan Zhang ◽  
Cheng Ping Zhang ◽  
Qian Qian Li ◽  
Zheng Li ◽  
Yi Cai
Keyword(s):  
Failure Process ◽  
Test Method ◽  
Test Results ◽  
Tunnel Engineering ◽  
Deformation And Failure ◽  
Tunnel Section ◽  
Section Size ◽  
Ground Cavity ◽  
Stratum Deformation ◽  
Beijing Subway

In order to study the influence of cavity above the tunnel on stratum deformation and failure in urban tunnelling, the model test method was adopted based on the parameters of the stratum and tunnel section size in Beijing subway. The stratum responses were obtained under the conditions without ground cavity and with ground cavity above the tunnel. The responses include the stratum stress distribution, stratum settlement law and stratum failure process. It was concluded that the existence of ground cavity above the tunnel worsened the stratum condition and accelerated the progress of stratum deformation and failure. Furthermore, the failure began from the cavity and the damage scope was bigger than that under the condition without cavity according to the test results. The research results can be referenced for the similar tunnel engineering.

scholarly journals Hybrid Simulation of Seismic Responses of a Typical Station with a Reinforced Concrete Column

2020 ◽  
Vol 10 (4) ◽  
pp. 1331 ◽  
Author(s):  
Xuesong Cai ◽  
Chengyu Yang ◽  
Yong Yuan
Keyword(s):  
Reinforced Concrete ◽  
Failure Process ◽  
Hybrid Simulation ◽  
Test Method ◽  
Shaking Table ◽  
Subway Station ◽  
Test Results ◽  
Earthquake Excitation ◽  
Simulation Process ◽  
Central Column

During the 1995 Kobe earthquake, damages were observed in the Daikai subway station and adjacent tunnels. It was the first large-scale underground structure that failed under the earthquake excitation. Numerical and experimental analyses have been conducted to study the failure process of the Daikai station. However, the issue of the scale ratio still exists in the shaking table tests of underground structures. In order to tackle this issue, a hybrid simulation technique is developed here to study the seismic performance of a typical subway station. Based on the previous research, it is found that the central column is the critical component of the structure. Therefore, a reinforced concrete central column is physically tested in the hybrid simulation process. On the other hand, the remaining parts of the structure and soil domain are numerically modeled at the same time. Four hybrid simulation cases are conducted with peak ground accelerations of 0.01 g, 0.1 g, 0.22 g, and 0.58 g. The test results of displacement and shear force are compared with the analytical results. Moreover, the good agreement between the test results and numerical results validate the accuracy of the proposed hybrid test method. After the hybrid simulation process, a quasi-static test is conducted to illustrate the mechanical properties of the central column after the earthquake excitation.

scholarly journals Research on Supporting Method for High Stressed Soft Rock Roadway in Gentle Dipping Strata of Red Shale

Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 423
Author(s):  
Chunde Ma ◽  
Jiaqing Xu ◽  
Guanshuang Tan ◽  
Weibin Xie ◽  
Zhihai Lv
Keyword(s):  
Failure Process ◽  
High Stress ◽  
Soft Rock ◽  
In Situ Stress ◽  
Mechanical Parameters ◽  
Deformation And Failure ◽  
Deep Mine ◽  
Plastic Energy ◽  
Roadway Stability ◽  
Phosphate Mine

Red shale is widely distributed among the deep mine areas of Kaiyang Phosphate Mine, which is the biggest underground phosphate mine of China. Because of the effect of various factors, such as high stress, ground water and so on, trackless transport roadways in deep mine areas were difficult to effectively support for a long time by using traditional supporting design methods. To deal with this problem, some innovative works were carried out in this paper. First, mineral composition and microstructure, anisotropic, hydraulic mechanical properties and other mechanical parameters of red shale were tested in a laboratory to reveal its deformation and failure characteristics from the aspect of lithology. Then, some numerical simulation about the failure process of the roadways in layered red shale strata was implemented to investigate the change regulation of stress and strain in the surrounding rock, according to the real rock mechanical parameters and in-situ stress data. Therefore, based on the composite failure law and existing support problems of red shale roadways, some effective methods and techniques were adopted, especially a kind of new wave-type bolt that was used to relieve rock expansion and plastic energy to prevent concentration of stress and excess deformation. The field experiment shows the superiorities in new techniques have been verified and successfully applied to safeguard roadway stability.

The Research of IC Test Based on LTX-77 Test System

2014 ◽  
Vol 496-500 ◽  
pp. 1176-1179
Author(s):  
Li Tan ◽  
Yu Fang
Keyword(s):  
Test Object ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Analog Ic ◽  
Test Platform ◽  
Logic Functions ◽  
Actual Test ◽  
Ic Test

LTX-77 test system is a large IC test system that is used for various kinds of analog IC, digital IC and analog digital mixed IC. It can be used to test DC parameters, AC parameters and logic functions. In the paper, the IC test platform is LTX-77 test system. IC ADC0804 was tested as the test object. The test method of IC is described in the view of actual test. The test results show that the test system is convenient and accurate, which has important practical value for IC manufacturers and users.

The Improved Friction Properties of Bonded MoS2 Films by MAO Treating of Al Substrate

2013 ◽  
Vol 275-277 ◽  
pp. 1911-1914 ◽  
Author(s):  
Han Jun Hu ◽  
Hui Zhou ◽  
Yu Gang Zheng ◽  
Kai Feng Zhang ◽  
Zhi Hua Wan
Keyword(s):  
Tribological Properties ◽  
Solid Lubricants ◽  
Ceramic Coatings ◽  
Test System ◽  
Test Method ◽  
Test Results ◽  
Specimen Test ◽  
Micro Arc Oxidation ◽  
A New Technique ◽  
Porous Microstructures

The bonded MoS2 films are widely used as solid lubricants in aerospace mechanisms due to their excellent tribological properties. Traditionally, the MoS2 was directly bonded on the Al substrate that was only treated by the technique named of sandblast. For improving the tribological properties of MoS2 films, micro arc oxidation (MAO) instead of sandblast was introduced as a new technique for treating of Al substrate. In this article, the tribological properties of MoS2 films which were bonded on different surface of Al substrate as mentioned above were discussed, respectively. It was concluded from the test results that the MoS2 films bonded on substrate treated by MAO have better tribological properties than those samples treated by sandblast. The endurance life against abrasion of the former is as high as twenty times of the latter by the stand test method of ball on disk using the UMT Multi-Specimen Test System. This test results could be illustrated by the following reasons. The first is the porous microstructures of MAO ceramic coatings on the Al substrate. The coatings have numerous pits to be good at increasing the binding force with the MoS2 films, and the pits can also provide a MoS2 lubricants reservoir during processes of friction. Both of them improved the MoS2 film’s ability of wear-protective. The second is that hardness of the coating is higher than the Al, and this ensures well wearing resistance, especially in practical application to big load-supporting moving parts, such as bearing, gear, etc…

Study on Conventional Domed Bursting Disc Material and Burst Pressure Test

2013 ◽  
Vol 690-693 ◽  
pp. 2371-2378
Author(s):  
Wei Pu Xu ◽  
Yi Ting Liu
Keyword(s):  
Stainless Steel ◽  
Tensile Test ◽  
316L Stainless Steel ◽  
Performance Test ◽  
Test Method ◽  
Burst Pressure ◽  
Test Results ◽  
Manufacturing Method ◽  
Pressure Test ◽  
Disc Material

A brief overview is given in the conventional domed bursting disc structure and manufacturing method. 316L stainless steel as a template is selected. With the investigation on bursting disc material tensile test method, the test results are summarized,also the burst results of disc burst pressure in different sizes. With the help of bursting disc material performance test and bursting disc burst pressure test of 316L , the test results provide a reference for other types of bursting disc.

Research on Hydraulic Conductivity of Coarse Sandstone under Triaxial Compression

2011 ◽  
Vol 94-96 ◽  
pp. 1146-1151 ◽  
Author(s):  
Guan Rong ◽  
Xiao Jiang Wang
Keyword(s):  
Hydraulic Conductivity ◽  
Circumferential Strain ◽  
Triaxial Compression ◽  
Confining Pressure ◽  
Test Results ◽  
Stress Strain ◽  
Deformation And Failure ◽  
Maximum Value ◽  
Strain Process ◽  
Peak Value

Permeability test for complete stress-strain process of coarse sandstone were carried out in triaxial test instrument. On the basis of test results, the influence of confining pressure and strain on the hydraulic conductivity was discussed. It is shown that in the complete stress-strain process, hydraulic conductivity changes in the law that presents the same character with the curve of stress-strain. The hydraulic conductivity reduces slightly with the increase of deviatoric stress in the stage of micro fracture compressing and elastic; In the elastoplastic stage, along with the expansion of new fractures, the hydraulic conductivity increases slowly at first and then reaches sharply to the maximum value after peak point; In the post-peak stage, the fracture which controls the hydraulic conductivity of coarse sandstone is compressed because of the confining pressure and the hydraulic conductivity decreases. During the process of deformation and failure, the hydraulic conductivity is more sensitive to the change of circumferential strain. With the increase of confining pressure, the increased value from initial to peak value and the decreased value from peak to residual value decreases.

scholarly journals Hedonic Test Method for Measuring Instant Pindang Seasoning Powder Preferences

2019 ◽  
Vol 3 (1) ◽  
pp. 34
Author(s):  
Dea Tio Mareta
Keyword(s):  
Test Method ◽  
Test Results ◽  
Drying Method ◽  
Typical Food ◽  
Hedonic Scale

Instant seasoning for cooking are commonly known by people who want something practical. Pindang is a typical food of Lampung and South Sumatra Province, consisting of various spices and herbs. Instant pindang seasoning powder made with foam mat drying method using 3 varations of foam additives. The purpose of this study was to determine the level of taste, aroma, and color of instant pindang seasoning powder made with three variations of foam additives, namely 5% (w/w), 10% (w/w), and 15% (w/w). The hedonic test for instant pindang seasoning powder were carried out on 35 panelists. Panelists were faced with 3 samples with 3 different sample numbers. Panelists were asked to assess how much preference for seasoning products using hedonic scale. The hedonic test results showed that, with the addition of 15% (w/w) foam is preferred in terms of color. As for aroma and taste, there were no significant differences between the three products. Keywords: foam mat drying , hedonic test, instant pindang seasoning powder, pindang

scholarly journals Pengaruh Latihan Dribbling With A Curving Line Trajectory Untuk Meningkatkan Keterampilan Dribbling Pemain Sepak Bola Ps. Undikam Mataram Tahun 2019

2019 ◽  
Vol 4 (4) ◽  
Author(s):  
Ismail Marzuki ◽  
Soemardiawan Soemardiawan
Keyword(s):  
Sampling Technique ◽  
Test Method ◽  
Soccer Players ◽  
Football Players ◽  
Test Results ◽  
Significance Level ◽  
Speed Test ◽  
Table Analysis ◽  
Observation Method ◽  
Line Trajectory

The focus of the problem in this research When competing frequently there are mistakes in dribbling, so from this it is necessary to have this exercise, to improve the dribbling skills of PS players. UNDIKMA Mataram. The purpose of this study is to determine whether there is an effect of Dribbling With A Curving Line Trajectory Exercise on the Dribbling Skills of PS Soccer Players. Mataram UNDIKMA 2019 ". The research methods used by researchers are the observation method, the documentation method and the deed test method. The study design uses a pretest-posttest design (initial test and final test). The population used in this study are all PS players. UNDIKMA Mataram in 2019. The number of samples in the study conducted was 22 which became a sample of 11 players PS soccer players. UNDIKMA Mataram. The sampling technique in this study using the saturation sampling technique is a sampling technique if all members of the population can be sampled. Analysis of statistical data with a significance level of 5% for the speed test results obtained by the t-value so from the results of research X1 (Dribbling With A Curving Line Trajectory, with Y1 obtained tcount is much greater than ttable, this shows that the hypothesis "Ha" (accepted ) then this research is significant, drawing conclusions from the table analysis at a significant level of 5% with a number of samples (n - 1) that is 11-1 = 10 at 1,812. Then it can be concluded that, 1) The Effect of Dribbling With A Curving Line Trajectory on Dribbling Skills PS Football Players. Mataram UNDIKMA 2019, Tcount> ttable (7.362> 1,812). 2). this shows that the hypothesis "Ha" (accepted) then this research is significant.

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