scholarly journals The Deviation of Semi-Theoretical and Semi-Empirical Water Inflow Prediction Formula Based on Sphere Coordinate Conversion and a Grouting Excavation Evaluation Method

2021 ◽  
Vol 11 (24) ◽  
pp. 11956
Author(s):  
Yonghong Wang ◽  
Jiabin Li ◽  
Chuan Wang ◽  
Qin He
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Fractured Rock ◽  
Water Inflow ◽  
Theoretical Formula ◽  
Simulation Methods ◽  
Confined Aquifer ◽  
Fractured Rock Mass ◽  
Numerical Simulation Methods ◽  
Weight Method

The water in the rock medium is exchanged with the confined aquifer through the fracture, which leads to the water inflow line in the confined aquifer is no longer horizontal. This paper assumes that the aquifuge is a kind of semi-isolation layer, while the first-order derivative of the total head slope line function within the influence of precipitation approaches the slope of the line connecting the top plate of the aquifuge with the spherical center. This hypothesis demonstrates the relationship between the bottom of the well water inflow and the complete well gushing water. Laplace’s equation for the spherical coordinate transformation is used to find the analytical solution of the water inflow for stable flow. The calculation results are in line with reality through actual engineering and numerical simulation methods. The current numerical simulation methods and theoretical methods mostly consider the aquifer in the ideal state, which is difficult to simulate the fractured rock mass. The theoretical formula proposed in this paper can more effectively reflect the actual seepage situation of fractured rock mass than other formulas. In addition, the combination of theoretical derivation, numerical simulation and field measurement can predict the water inflow more accurately than unilateral research. At the same time, for the question of whether the face excavation is grouted or not, this paper using the subjective and objective assignment weight method combined with analytic hierarchy process method and entropy-weight method to take the weight calculation and giving a slurry excavation judgment method based on the proposed formula. Theoretical support is given for the selection of permeability coefficients for each hole in the overrun exploration and this method is validated by different projects, which has some degree of reference value.

scholarly journals A STUDY ON RISK ASSESSEMENT APPROACH OF WATER INFLOW INTO A SHAFT IN FRACTURED ROCK MASS

2010 ◽  
Vol 66 (2) ◽  
pp. 370-386
Author(s):  
Takayuki MOTOSHIMA ◽  
Hironori ONOE ◽  
Yuji IJIRI ◽  
Hiroyasu OHTSU ◽  
Hiromitsu SAEGUSA
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Water Inflow ◽  
Fractured Rock Mass ◽  
Risk Assessement

scholarly journals Calculation of Elastic Modulus for Fractured Rock Mass Using Dimensional Analysis Coupled with Numerical Simulation

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Fengyu Ren ◽  
Jing Zhang ◽  
Zhihua Ouyang ◽  
Hao Hu
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Elastic Modulus ◽  
Dimensional Analysis ◽  
Underground Mining ◽  
Fractured Rock ◽  
Continuum Theory ◽  
Equivalent Model ◽  
Fractured Rock Mass ◽  
Natural Rock

Underground mining activities make the fractures in the natural rock mass develop randomly. The elastic modulus of the fractured rock mass Em is changed with the redistribution and development of the fractures. An equivalent model of fractured rock mass is structured to represent the hydraulic conductivity and the rock mass strain because of the continuum theory. Dimensional analysis is very useful to build relationship of the parameters in complex physical phenomena. Based on the engineering phenomenon of groundwater flowing into the goaf along the fracture in the rock mass, a fuzzy expression among parameters such as the parameter Em, the seepage flow Q, and the exposed area of the goaf A is obtained using dimensionless analysis. To calculate the parameter Em, the fuzzy relationship is then characterized by Darcy’s law and numerical simulation. Under the scripting environment of Python, an automated program to realize the numerical simulation of all scenarios is established, which also provides convenience for drawing the dimensionless flux charts. The results show that the parameter Em can be calculated by the dimensional analysis coupled with numerical simulation. In addition, the parameter Em decreases with the increase of the parameter Q, and the integrity of rock mass is also worse. Finally, a mine example is used to verify the feasibility of the method.

The Calculation of Grouting Diffusion Radius on Based Bingham Fluid for Chunnel That Passes through Fractured Rock Mass

2012 ◽  
Vol 256-259 ◽  
pp. 1280-1286
Author(s):  
Lei Wang ◽  
Tao Li
Keyword(s):  
Rock Mass ◽  
Calculation Result ◽  
Fractured Rock ◽  
Bingham Fluid ◽  
Theoretical Formula ◽  
Fractured Rock Mass ◽  
Real Situation ◽  
Grouting Pressure ◽  
Calculation Results ◽  
Design Requirements

To conduct pro-grouting design and make the prediction of the result of grouting about the chunnel that passes through fractured rock mass, the essay adopts following theoretical formula to calculate the fractured rock mass grouting diffusion radius: Wittke and Wallner Formula、Lombadi Formula and Huang Chunhua Formula. Finally through the analysis of calculation results can conclude: (I) The diffusion radius of the slurry can meet the design requirements under the condition of 3-4 Mpa designed grouting pressure、5 cm grouting holes’ radius and 1800-3600s grouting time. (II) The calculation result of Huang Chunhua Formula is almost the same as Wittke and Wallner Formula and Lombadi Formula, but the margin of grouting diffusion radius’ change as grouting time and grouting pressure growing are different, it’s more close to the real situation.(III) The calculation of these theoretical formula only consider the breadth of fractured rock without considering the variation of its thickness and direction. So all of the calculation results of these formula are generally bigger than the standard.

The Prediction of the Water Inflow by Numerical Simulation Methods of Huijiabao Mine, Guizhou Province

2015 ◽  
Vol 744-746 ◽  
pp. 1161-1164 ◽  
Author(s):  
Chen Chen Li ◽  
Shi Guang Xu ◽  
Jun Jie Ba
Keyword(s):  
Numerical Simulation ◽  
Groundwater Flow ◽  
Water Inrush ◽  
Laboratory Data ◽  
Mineral Resources ◽  
Water Inflow ◽  
Guizhou Province ◽  
Natural State ◽  
Simulation Methods ◽  
Numerical Simulation Methods

The mineral resources in our country is variety and huge reserves, but there are still many problems in the mining process. Among the problems, the water burst and water inrush are much more prominent. Through full and comprehensive analysis of previous studies collected data and laboratory data and field investigations, based on the long-term observations of the natural state steady groundwater flow of Huijiabao mine, and the unsteady groundwater flow of the pumping tests in Changtian well, and other tests, Combined with the actual production situation, it predicted the water inflow on the 1000 meters level of Huijiabao mine of Guizhou Province by numerical simulation methods to provides the safety production of mining.

Seepage Numerical Simulation Methods of Hard Fractured Rock Mass

2013 ◽  
Vol 423-426 ◽  
pp. 1330-1333
Author(s):  
Gang Lei
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Permeability Coefficient ◽  
Hard Rock ◽  
Fractured Rock ◽  
Triaxial Compression ◽  
Equivalent Plastic Strain ◽  
Simulation Method ◽  
Numerical Simulation Methods ◽  
Fissure Water

According to the seepage action of hard rock fissure water, a numerical simulation method is proposed in this paper. The basic mechanical properties for rock mass changed significantly during the process of secondary stress adjustments, and the rock deterioration constitutive model (RDM) can accurately reflect both the abruptness of the rock yield failure and the changes of mechanical parameters after yield. On the basis of RDM, the permeability coefficient with equivalent plastic strain function was introduced in this method which can update the permeability coefficient, and carried out numerical simulation on hard rock fissure water seepage action by FLAC3D. The results of the seepage triaxial compression experiment proved the rationality of the method.

Mechanism of Water Inflow of Subsea Tunnel Induced by Blasting Excavation

2013 ◽  
Vol 353-356 ◽  
pp. 1566-1571
Author(s):  
Yong Sheng Liu ◽  
Jian Guo Peng ◽  
Jing Hua Zhang ◽  
Li Xin Fu
Keyword(s):  
Rock Mass ◽  
Stress Field ◽  
Fractured Rock ◽  
Water Pressure ◽  
In Situ Stress ◽  
Static Stress ◽  
Water Inflow ◽  
Fractured Rock Mass ◽  
Blasting Excavation ◽  
Subsea Tunnel

Water inflow was the main damage during blasting excavation of subsea tunnel, disturbance due to blasting could also induce water inflow. Based on the blasting mechanism of water-bearing fractured rock-mass, stress state and breaking-down process of the fracture was analyzed, which was affected by dynamic stress field (blasting effect) and static stress field (water and in-situ stress). With the affect of overlapping dynamic and static stress field, the calculation formula of the critical inner water pressure in water inflow was presented. At last, using these formulas, critic water press and radial extent were calculated of water-bearing fractured rock-mass in Xiamen subsea tunnel.

Computer Aided Design for Safety Analysis of Excavation in Stratified Rock Tunnel

2011 ◽  
Vol 71-78 ◽  
pp. 3197-3200
Author(s):  
Shu Yun Wang ◽  
Xiong Gang Xie ◽  
Xi Chen
Keyword(s):  
Numerical Simulation ◽  
Rock Mass ◽  
Computer Aided Design ◽  
Rapid Development ◽  
Deformation Analysis ◽  
Simulation Methods ◽  
Computer Technique ◽  
Numerical Simulation Methods ◽  
Stratified Rock ◽  
Stratified Rock Mass

Stratified rock mass is widely existing in tunnel engineering. The most relevant feature of stratified rocks is the occurrence of very persistent bedding, which makes the rock-mass highly non-isotropic. A number of techniques for designing underground excavations in stratified media have been described in the literature, like theoretical method and laboratory test, which can only be applied in analyzing the problem with simple geometry and costs much expense. Recently, with rapid development of computer technique, numerical simulation methods have been widely applied in engineerin. Among all the numerical simulation methods, fast lagrangian explicit finite difference code of continua (FLAC3D) is widely used to solve practical problems, especially in field of elasto-plastic characteristic, large deformation analysis and construction procedure. So in the present paper, numerical simulation for the failure mode of stratified rock mass after tunnel excavation is done by FLAC3D, which can give further guidance to understand the anisotropic characteristic of stratified rock mass.

Sign in / Sign up

Export Citation Format

Share Document