Anisotropic characteristic of irregular columnar-jointed rock mass based on physical model test

2016 ◽  
Vol 21 (5) ◽  
pp. 1728-1734 ◽  
Author(s):  
Zhinan Lin ◽  
Weiya Xu ◽  
Huanling Wang ◽  
Jiuchang Zhang ◽  
Wang Wei ◽  
...  
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Model Test ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Physical Model Test ◽  
Columnar Jointed Rock Mass

scholarly journals Geomechanical Model Experiment Study on Deformation and Failure Mechanism of the Mountain Tunnel in Layered Jointed Rock Mass

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Zhibiao Guo ◽  
Jinyan Fan ◽  
Fengnian Wang ◽  
Hongbo Zhou ◽  
Wei Li
Keyword(s):  
Rock Mass ◽  
Failure Mechanism ◽  
Model Test ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Physical Model Test ◽  
Correlation Technique ◽  
Large Area ◽  
Rock Mass Structure ◽  
Deformation And Failure

The Minxian tunnel is a key engineering of the Weiyuan-Wudu expressway that is excavated in layered jointed carbonaceous slate rock mass. During the construction process, the surrounding rocks of the tunnel encountered serious large deformations and failure, which brought about great difficulties to the safety and cost of the tunnel. In order to study the deformation and failure mechanism of the surrounding rocks, a physical model test was conducted, and integrated methods including strain gauges, a digital camera, and noncontact full-field digital imaging correlation technique were used to record the response information of the surrounding rocks. The evolution process of surrounding rocks failure was simulated successfully in the model test, and the deformation characteristics were basically consistent with the actual engineering. The modelling results show that concentrated stresses in the surrounding rocks were very uneven due to developed stratified and jointed rock mass structure. The maximum and minimum concentrated stresses appeared at the vault of the tunnel and left of inverted arc area, and concentration factors were 3.11 and 1.98, respectively. The main forms of surrounding rocks deformation and failure were large area spalling of surface, severe circumferential fractures, serious bending deformations of thin rock layers, and collapse of overlying strata. The maximum displacements occurred at left sidewall and right shoulder of the tunnel and the corresponding actual displacements were 460 mm to 500 mm. Caving and failure took place firstly at several key positions with maximum concentrated stresses or displacements and subsequently gave rise to massive collapse of surrounding rocks.

Model Test Study on Influences of Layered Rock Mass Dip Angle on Stability of Deep-Buried Tunnel

2011 ◽  
Vol 90-93 ◽  
pp. 2363-2371
Author(s):  
Bin Wei Xia ◽  
Ke Hu ◽  
Yi Yu Lu ◽  
Dan Li ◽  
Zu Yong Zhou
Keyword(s):  
Rock Mass ◽  
Physical Model ◽  
Model Test ◽  
Physical Models ◽  
Physical Model Test ◽  
Stress Distributions ◽  
Failure Characteristics ◽  
Layered Rock ◽  
Layered Rock Mass ◽  
Dip Angle

Physical models of layered rock mass with different dip angles are built by physical model test in accordance with the bias failure characteristics of surrounding rocks of layered rock mass in Gonghe Tunnel. Bias failure characteristics of surrounding rocks in thin-layered rock mass and influences of layered rock mass dip angle on stability of tunnel are studied. The research results show that failure characteristics of physical models generally coincide with those of surrounding rocks monitored from the tunnel site. The failure regions of surrounding rock perpendicular to the stratification planes are obviously larger than those parallel to. The stress distributions and failure characteristics in the surrounding rocks are similar to each physical model of different dip angles. The stress distributions and failure regions are all elliptic in shape, in which the major axis is in the direction perpendicular to the stratification planes while the minor axis is parallel to them. As a result, obvious bias failure of surrounding rocks has gradually formed. The physical model tests provide reliable basis for theoretical analysis on the failure mechanism of deep-buried layered rock mass.

scholarly journals Study on the mechanical behaviour of Columnar Jointed Rock Mass under uniaxial compression state

2021 ◽  
Vol 861 (7) ◽  
pp. 072106
Author(s):  
Z P Xiang ◽  
S L Huang ◽  
H L Wang ◽  
W Y Xu ◽  
X L Ding ◽  
...  
Keyword(s):  
Rock Mass ◽  
Uniaxial Compression ◽  
Mechanical Behaviour ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Columnar Jointed Rock Mass

scholarly journals The Method of Determining Excavation Damaged Zone by Acoustic Test and the Application in Engineering Cases

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Qian-Cheng Sun ◽  
Hao-Sen Guo ◽  
Zhi-Hua Xu ◽  
Yue Liu ◽  
Xiao Xu
Keyword(s):  
Rock Mass ◽  
Damage Evolution ◽  
Hard Rock ◽  
Damage Zone ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Excavation Damaged Zone ◽  
Damaged Zone ◽  
Columnar Jointed Rock Mass

It is very important to accurately determine the depth of excavation damaged zone for underground engineering excavation and surrounding rock stability evaluation, and it can be measured by acoustic test, but there is no quantitative method for analysis of the results, and it relies heavily on the experience of engineers, which leads to the low reliability of the results and also limits the application of the acoustic method. According to substantial field test data and the feedback of surrounding rock support parameters, the boundary method is proposed to determine the depth of excavation damaged zone in surrounding rock based on the relation between the ultrasonic velocity of measured point and the background wave velocity of rock mass. When the method is applied to the columnar jointed rock mass of Baihetan and the deep-buried hard rock of Jinping, the excavation damaged zone was well judged. The results in the Baihetan project show that the proposed method of determining excavation damage zone by the acoustic test can well demonstrate the anisotropy characteristics of the columnar jointed rock mass, and the damage evolution characteristics of jointed rock mass at the same position can also be obtained accurately. Moreover, the method also can accurately reveal the damage evolution process of the deep-buried hard rock under the condition of high ground stress, which proved the applicability of this method in jointed or nonjointed rock masses.

Physical and numerical tests of the excavation walls in jointed rock masses

2014 ◽  
Vol 51 (5) ◽  
pp. 554-569 ◽  
Author(s):  
Moorak Son ◽  
Jaehyun Park
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Earth Pressure ◽  
Jointed Rock ◽  
Physical Model Test ◽  
Rock Masses ◽  
Jointed Rock Masses ◽  
Rock Types ◽  
Joint Characteristics ◽  
Parametric Studies

This paper examines the magnitude and distribution of earth pressure on the support systems of open cuts in jointed rock masses. A physical model test was carried out using concrete blocks with man-made joints to represent a jointed rock mass. The model test was simulated numerically to provide a justifiable basis for extended numerical parametric studies. This study focused on the overall procedures of the physical model test, its numerical simulation, and extended numerical parametric studies. A comparison of the results from both the physical model test and numerical simulation confirmed that the applied numerical approach and methodology were suitable for further extended numerical parametric studies. The controlled parameters were the different rock types and joint characteristics including joint shear condition, joint spacing, and joint inclination angle. Results of the earth pressures from the numerical parametric tests in jointed rock masses were compared with Peck’s empirical earth pressure for soil ground. The comparison showed that the earth pressure in jointed rock masses can be very different from that in the soil ground. Accordingly, the effect of the rock types and joint characteristics needs to be considered when designing excavation support systems in jointed rock masses.

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