scholarly journals Development and Application of the 3D Model Test System for Water and Mud Inrush of Water-Rich Fault Fracture Zone in Deep Tunnels

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yanhui Guo ◽  
Zhijun Kong ◽  
Jin He ◽  
Ming Yan
Keyword(s):  
Stress Field ◽  
Fault Zone ◽  
Model Test ◽  
Water Pressure ◽  
Surrounding Rock ◽  
Physical Model Test ◽  
Loading System ◽  
Similar Materials ◽  
Water And Mud Inrush ◽  
Ground Stress

In order to study the evolution process, damage characteristics, and occurrence mechanism of water and mud inrush disaster in deep tunnel fault zone with infiltration instability under complex conditions, a set of the three-dimensional physical model test systems of water and mud inrush flow-solid coupling in tunnel fault zones is developed. The system mainly comprises a rigid test frame, ground stress loading system, hydraulic loading system, multiple information monitoring and acquisition system, and mud and water protrusion recovery system. The system’s main features are that it can meet the model’s simulation of the ground stress field, water pressure, and other complex environments subjected to ground stress, and water pressure gradients can be controlled. The system is characterized by high rigidity, high-pressure strength, visualization, good sealing, and expandability. Taking the water fault zone of a well in the Dazhu Mountain Tunnel of the Darui Railway as the research object, the new fault zone and surrounding rock similar materials applicable to the flow-solid coupling model test are designed using the self-developed flow-solid coupling similar materials. The system is used for model tests to reveal the spatial and temporal changes of the surrounding rock stress field and seepage field during the tunnel excavation process. The test results show that the system is stable and reliable, and the research method and results are of guiding significance to the research of the same type of underground engineering.

scholarly journals Analysis of Tunnel Water Inrush Considering the Influence of Surrounding Rock Permeability Coefficient by Excavation Disturbance and Ground Stress

2021 ◽  
Vol 11 (8) ◽  
pp. 3645
Author(s):  
Helin Fu ◽  
Pengtao An ◽  
Long Chen ◽  
Guowen Cheng ◽  
Jie Li ◽  
...  
Keyword(s):  
Permeability Coefficient ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Water Inflow ◽  
Calculation Error ◽  
External Water Pressure ◽  
Ground Stress ◽  
External Water ◽  
Inflow Prediction

Affected by the coupling of excavation disturbance and ground stress, the heterogeneity of surrounding rock is very common. Presently, treating the permeability coefficient as a fixed value will reduce the prediction accuracy of the water inflow and the external water pressure of the structure, leading to distortion of the prediction results. Aiming at this problem, this paper calculates and analyzes tunnel water inflow when considering the heterogeneity of permeability coefficient of surrounding rock using a theoretical analysis method, and compares with field data, and verifies the rationality of the formula. The research shows that, when the influence of excavation disturbance and ground stress on the permeability coefficient of surrounding rock is ignored, the calculated value of the external water force of the tunnel structure is too small, and the durability and stability of the tunnel are reduced, which is detrimental to the safety of the structure. Considering the heterogeneity of surrounding rock, the calculation error of water inflow can be reduced from 27.3% to 13.2%, which improves the accuracy of water inflow prediction to a certain extent.

scholarly journals Experimental Study on the Ratio of Similar Materials in Weak Surrounding Rock Based on Orthogonal Design

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Pengfei Jiao ◽  
Xiao Zhang ◽  
Xinzhi Li ◽  
Bohong Liu ◽  
Haojie Zhang
Keyword(s):  
Model Test ◽  
Orthogonal Design ◽  
Surrounding Rock ◽  
Similar Material ◽  
Geomechanical Model ◽  
Geomechanical Model Test ◽  
Geological Conditions ◽  
Key Factor ◽  
Similar Materials ◽  
Weak Surrounding Rock

In the aspect of stability analysis of tunneling engineering, geomechanical model test is an important research method. A similar material is the prerequisite for the success of geomechanical model test. In the field of major engineering applications, a variety of similar materials are prepared for different geological conditions of surrounding rock and applied in some major engineering. With the use of standard sand, fine sand, and silt clay as materials, similar materials for weak surrounding rock were developed. Based on the orthogonal design method, through the direct shear test, the range analysis and variance analysis of various factors affecting the physical and mechanical parameters of weak surrounding rock are carried out. The results show similar material can meet the requirements in weak surrounding rock. Standard sand is the key factor that influences the internal friction angle of similar materials, and silt clay is the key factor affecting the cohesion of similar materials. Similar materials can meet the elastic modulus and severe requirements of the weak surrounding rock and can be used for the weak surrounding rock engineering. The new type of similar material configuration is widely used in shallow buried tunnel entrance section and urban shallow buried excavation engineering, in addition to tunnel engineering in loess stratum, and the problems of engineering design and construction are solved through geomechanical model test.

scholarly journals Analysis on Water Inrush Process of Tunnel with Large Buried Depth and High Water Pressure

Processes ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 134 ◽  
Author(s):  
Weimin Yang ◽  
Zhongdong Fang ◽  
Hao Wang ◽  
Liping Li ◽  
Shaoshuai Shi ◽  
...  
Keyword(s):  
High Pressure ◽  
Model Test ◽  
Water Pressure ◽  
Water Inrush ◽  
High Water ◽  
Surrounding Rock ◽  
Karst Cave ◽  
Tunnel Excavation ◽  
Pressure Water ◽  
High Water Pressure

In order to explore the catastrophic evolution process for karst cave water inrush in large buried depth and high water pressure tunnels, a model test system was developed, and a similar fluid–solid coupled material was found. A model of the catastrophic evolution of water inrush was developed based on the Xiema Tunnel, and the experimental section was simulated using the finite element method. By analyzing the interaction between groundwater and the surrounding rocks during tunnel excavation, the law of occurrence of water inrush disaster was summarized. The water inrush process of a karst cave containing high-pressure water was divided into three stages: the production of a water flowing fracture, the expansion of the water flowing fracture, and the connection of the water flowing fracture. The main cause of water inrush in karst caves is the penetration and weakening of high-pressure water on the surrounding rock. This effect is becoming more and more obvious as tunnel excavation progresses. The numerical simulation results showed that the outburst prevention thickness of the surrounding rock is 4.5 m, and that of the model test result is 5 m. Thus, the results of the two methods are relatively close to each other. This work is important for studying the impact of groundwater on underground engineering, and it is of great significance to avoid water inrush in tunnels.

Scaled Physical Model Test on Underground Gas Storages Based on a Pneumatically Flexible Loading System

2016 ◽  
Vol 44 (6) ◽  
pp. 20140346
Author(s):  
Xuguang Chen ◽  
Tianbin Li ◽  
Qiangyong Zhang ◽  
Shucai Li
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Physical Model Test ◽  
Loading System

scholarly journals Elastic-plastic analysis and shrinkage properties study of swelling rock borehole in coalmine

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Jifeng Hou ◽  
◽  
Zhongping Guo ◽  
◽  
Keyword(s):  
Stress Field ◽  
Plastic Zone ◽  
Water Content ◽  
Radial Displacement ◽  
Water Pressure ◽  
Borehole Wall ◽  
Elastic Plastic ◽  
Ground Stress ◽  
Swelling Rock ◽  
Humidity Field

The borehole shrinkage of swelling rock in coalmine is a complex problem affected by the combination of multiple fields, such as humidity field and stress field. By establishing the equilibrium equation of swelling rock borehole in coalmine, considering the expansion and softening properties, an elastic-plastic mechanics analysis was carried out, and the plastic zone radius and radial displacement of swelling rock borehole in coalmine were determined under the combination of humidity field and stress field. Taking the floor rock roadway in the 8# coal seam of Songzao Coalmine in Chongqing as an example, the influence laws of water content, ground stress, and water pressure in the hole on the borehole shrinkage were studied. The results show that, with the increase of water content of the surrounding rock, the radius of plastic zone and radial displacement of borehole wall gradually increase. Both the humidity expansion and softening have an important influence on borehole shrinkage in coalmine, and the radial displacement of borehole wall under the combination of swelling and softening is greater than that of only considering expansion or softening. With the increase of ground stress, the radius of plastic zone and radial displacement of borehole wall gradually increase, showing a nonlinear increasing relation. The larger the water pressure in the borehole, the smaller the radius of plastic zone and radial displacement of borehole wall, and properly increasing the water pressure in the borehole can effectively control the borehole shrinkage. The accuracy of theoretical analysis was further r verified by similar model tests. The results can provide a theoretical basis for solving the problem of borehole shrinkage in the swelling rock of coalmine.

scholarly journals A Model of Anisotropic Property of Seepage and Stress for Jointed Rock Mass

2013 ◽  
Vol 2013 ◽  
pp. 1-19 ◽  
Author(s):  
Pei-tao Wang ◽  
Tian-hong Yang ◽  
Tao Xu ◽  
Qing-lei Yu ◽  
Hong-lei Liu
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Underground Mining ◽  
Principal Direction ◽  
Water Pressure ◽  
Jointed Rock ◽  
Jointed Rock Mass ◽  
Surrounding Rock ◽  
Metal Mine ◽  
Roadway Stability

Joints often have important effects on seepage and elastic properties of jointed rock mass and therefore on the rock slope stability. In the present paper, a model for discrete jointed network is established using contact-free measurement technique and geometrical statistic method. A coupled mathematical model for characterizing anisotropic permeability tensor and stress tensor was presented and finally introduced to a finite element model. A case study of roadway stability at the Heishan Metal Mine in Hebei Province, China, was performed to investigate the influence of joints orientation on the anisotropic properties of seepage and elasticity of the surrounding rock mass around roadways in underground mining. In this work, the influence of the principal direction of the mechanical properties of the rock mass on associated stress field, seepage field, and damage zone of the surrounding rock mass was numerically studied. The numerical simulations indicate that flow velocity, water pressure, and stress field are greatly dependent on the principal direction of joint planes. It is found that the principal direction of joints is the most important factor controlling the failure mode of the surrounding rock mass around roadways.

scholarly journals Study on the Geo-Stress Loading and Excavation Unloading Devices of the Large-Scale Photoelastic Model Test for Deep-Buried Tunnels

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jiaqi Guo ◽  
Binzhong Zhu ◽  
Xiliang Liu ◽  
Jing Luo ◽  
Zhaoyuan Li
Keyword(s):  
Model Test ◽  
Surrounding Rock ◽  
Test Method ◽  
Original Design ◽  
Simulation Test ◽  
Supporting Structure ◽  
Photoelastic Model ◽  
Loading System ◽  
The Stability ◽  
Current Loading

At present, theoretical analysis, numerical simulation, and other methods cannot be used to properly solve the problems associated with the stability and bearing capacity of the surrounding rock and its supporting system, the interaction between the supporting structure and surrounding rock, and the sharing role of each supporting structure, all of which commonly occur in deep tunnels. The model test method represented by the photoelastic test is still an important approach to study this kind of problem. In view of the deficiency of the current loading system of the photoelastic model test, we developed a geo-stress loading system for the photoelastic model test, which can simulate the in situ geo-stress environment of unidirectional loading, bidirectional equal pressure, bidirectional unequal pressure, and tridirectional unequal pressure. The universal retaining force loading rod can realize the stability and effective compensation of loading, which is an original design. According to the principle of umbrella-shaped expansion and contraction mechanism, an excavation unloading device for the photoelastic model test is developed, which can realize the simulation of various degrees of displacement release in the excavation process of deep tunnels and other underground projects. The loading simulation test and excavation unloading simulation test show that the geo-stress loading system and excavation unloading device developed in this paper are flexible, exhibit good performance, and can fully achieve their respective test functions. The combination of two devices can compensate for the insufficiency of the current photoelastic model test and will promote the application of photoelastic model tests in underground engineering applications such as deep tunnel projects.

scholarly journals Comparative Analysis of Roadway Reinforcement Effects Based on Fluid-Solid Coupling in the Fractured Zone of Water-Rich Fault

2018 ◽  
Vol 2018 ◽  
pp. 1-14
Author(s):  
Jihua Zhang ◽  
Yun Dong ◽  
Yadong Chen ◽  
Yang Jiang ◽  
Huasheng Sun ◽  
...  
Keyword(s):  
Fault Zone ◽  
Permeability Coefficient ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Water Inrush ◽  
Surrounding Rock ◽  
Fractured Zone ◽  
Transient Electromagnetic ◽  
Working Face ◽  
Fissure Water

Water inrush is a common geological disaster during the roadway excavation process in the broken zone of water-rich faults. In this paper, the 15107 mining roadway built by Yuxing coal mine in such a fault zone was used as a case study to determine the water content of the surrounding rocks and a fault zone using the transient electromagnetic method (TEM). Also, the mechanics characteristics of such rocks in both saturated and unsaturated states were analyzed, a computational model for fluid-solid coupling in the water-rich fault fracture zone was established, and the permeability coefficient of the rocks under both shield support and bolt-grouting support was compared, along with analyzing the changes in pore pressure, fissure water velocity, and characteristics of deformation in the surrounding rocks. The numerical simulation results show that the fault range has an influence of about 20 m, which causes the forms of permeability coefficient to change like a hump. The permeability coefficient in the fractured zone is the largest, and the mutation rate at the fault plane is faster. Bolting not only reduces the permeability coefficient of the surrounding rock that is 1/10 of the beam support but also prevents the roof fissure water inrushing the roadway and the surrounding rock of the floor, while also causing the pore-water pressure to decrease, even reduce to zero, in front of the working face and floor. The flow velocity of the fissure water can be decreased by bolting, which can effectively control the deformation of the surrounding rock by 38.7%∼65% compared with the shield support. The practice results show that this method can effectively recover the cracks surrounding the mining roadway and stop gushing water. Concurrently, it successfully controls deformation of the surrounding rocks in the fault zone, thus ensuring stability of the roadway and facilitating safer mining production.

scholarly journals Model Test and Numerical Analysis on the Deformation and Stability of a Landslide Subjected to Reservoir Filling

Geofluids ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xinli Hu ◽  
Chuncan He ◽  
Chang Zhou ◽  
Chu Xu ◽  
Han Zhang ◽  
...  
Keyword(s):  
Water Level ◽  
Physical Model ◽  
Pore Water ◽  
Model Test ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Physical Model Test ◽  
Landslide Stability ◽  
Landslide Deformation ◽  
Reservoir Filling

Reservoir filling can affect the landslide stability and cause the landslide deformation within the reservoir area. In this paper, a physical model test and a series of numerical analyses were combined to investigate the landslide deformation and stability under reservoir filling. The surface deformation, deep displacement, and pore water pressure were recorded during the physical model test. In the model test, the increasing period of the pore water pressure inside the landslide is proposed to be a critical period for the landslide subjected to the reservoir filling. During this period, large landslide deformation occurred. The numerical analyses show that a greater factor of safety (FOS) appeared under a higher water level rising rate or a lower permeability coefficient during the water level rising stage when other variables are fixed, due to the domination of the reservoir buttressing effect which can increase the landslide resistance. During the reservoir maintaining stage, the reservoir water infiltrated into the landslide continuously to cause the matric suction dissipation and pore water pressure increase, which reduced the landslide shear strength and then decreased the landslide stability.

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