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.

scholarly journals Numerical Analysis of the Mud Inflow Model of Fractured Rock Mass Based on Particle Flow

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Yongjian Pan ◽  
Huajun Wang ◽  
Yanlin Zhao ◽  
Qiang Liu ◽  
Shilin Luo
Keyword(s):  
Rock Mass ◽  
Pressure Gradient ◽  
Flow Direction ◽  
Fractured Rock ◽  
Water Pressure ◽  
Water Inrush ◽  
Quadratic Function ◽  
Particle Flow ◽  
Fractured Rock Mass ◽  
Particle Flows

Water inrush and mud outburst are one of the crucial engineering disasters commonly encountered during the construction of many railways and tunnels in karst areas. In this paper, based on fluid dynamics theory and discrete element method, we established a fractured rock mass mud inflow model using particle flow PFC3D numerical software, simulated the whole process of fractured rock mass mud inflow, and discussed the effect of particle size and flow velocity on the change of pressure gradient. The numerical simulation results show that the movement of particles at the corner of the wall when the water pressure is first applied occurs similar to the vortex phenomenon, with the running time increases, the flow direction of particles changes, the vortex phenomenon disappears, and the flow direction of particles at the corner points to the fracture; in the initial stage, the slope of the particle flows rate curves increases in time, and the quadratic function is used for fitting. After the percolation velocity of particles reaches stability, the slope of the curve remains constant, and the primary function is used for fitting; the particle flow rate and pressure gradient are influenced by a variety of factors, and they approximately satisfy the exponential function of an “S” curve.

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

The Study of Fractured Rock Mass Instability of the Law Based on the Hydraulic Fracturing

2012 ◽  
Vol 496 ◽  
pp. 538-541
Author(s):  
Zhi Qiang Kang ◽  
Wein Jie Li ◽  
Yu Bo Jia
Keyword(s):  
Rock Mass ◽  
Hydraulic Fracturing ◽  
Hydraulic Fracture ◽  
Fractured Rock ◽  
Water Pressure ◽  
Overburden Rock ◽  
Fractured Rock Mass ◽  
Water Seepage ◽  
Vertical Loading ◽  
The Law

Fractured rock mass, Hydraulic fracture, RFPA2D-Flow, Instability of the law. Abstract. Based on the theory of fluid-solid coupling, Studying on the effect of permeability about damage and stress, Analysis of influence factors what hydraulic fracturing process, fracture propagation pattern, and influencing factors including shape and magnitude of inlet hole, stress conditions, and specimen strength were investigated. Application of rock failure process analysis software coupled seepage-stress F-RFPA2D, numerical simulated rock water pressure to cause crack rupture instability process, research the fracture law of the rock on water pressure and vertical loading. Combine similar physical experiment model, contrast analysis of two broken results and stress-strain curve, reveals instability mechanical behavior of rock hydraulic fracture process. Obtain deep mining in the process of mine water seepage and water extrude, overburden rock crack up, expand, water seepage, water extrude, instability rupture process rules.

Research on Seepage Field in Fractured Rock Mass of Underground Oil Storage Cave Using Distinct Element Method

2013 ◽  
Vol 353-356 ◽  
pp. 619-623
Author(s):  
Song Yu ◽  
Yun Peng Zhang ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Water Pressure ◽  
Hydraulic Pressure ◽  
Fractured Rock Mass ◽  
Water Curtain ◽  
Oil Storage ◽  
Underground Caverns ◽  
Element Method

The distribution of hydraulic pressure in fractured rock mass surrounding caverns after excavation and technique of stochastic generation of joint network are investigated based on discrete element method. In order to seal the oil in underground caverns with water in the actual engineering, a water curtain with water pressure is installed, and the changes of hydraulic pressure are simulated with a series of curtain pressures. It is shown that some joints that have been drained out during excavation can not be saturated if the water curtain pressure is less than a certain value. Water curtain pressure with a certain value gives a strong safe guarantee of saving oil in the underground petroleum storage caverns.

Study on Seepage Field of Artificial Water Curtains for Underground Petroleum Storage Caverns in Fractured Rock Mass

2013 ◽  
Vol 353-356 ◽  
pp. 1666-1670
Author(s):  
Yun Peng Zhang ◽  
Song Yu ◽  
Wei Shen Zhu
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Distinct Element ◽  
Water Pressure ◽  
Underground Water ◽  
Calculation Model ◽  
Fractured Rock Mass ◽  
Water Curtain ◽  
Underground Caverns ◽  
Water Seal

Based on joint statistics from the in-situ survey, using numerical simulation technique of joint network (Monte-Carlo method), the calculation model of fractured rock mass is generated. Underground seepage discharge filed in fractured rock mass surrounding storage caverns is analyzed by using distinct element method. The result of simulation has shown good agreement with surveying data. Two cases have been simulated that is water curtains is installed and is not installed. Water pressure distributions in joints are investigated in these two cases. It is shown that in the case without water curtain the groundwater in joints which locate the upper of underground caverns is drained out and water sealed conditions is completely unrealized. When water curtain pressure is set at 0.3MPa, can underground water seal the storage caverns.

scholarly journals Experimental Study of Joint Roughness Influence on Fractured Rock Mass Seepage

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Zhongxi Tian ◽  
Chunquan Dai ◽  
Qingshuang Zhao ◽  
Zhaobo Meng ◽  
Baoliang Zhang
Keyword(s):  
Rock Mass ◽  
Fractured Rock ◽  
Water Pressure ◽  
Rock Fracture ◽  
Single Fracture ◽  
Fractured Rock Mass ◽  
Joint Roughness ◽  
Joint Surfaces ◽  
The Mean ◽  
Mean Variance

Surrounding rock pressure, water pressure, and joint roughness are the important factors that affect the fractured rock mass seepage. It is of great significance to quantify the influence of these factors through experiments. In this study, rock fracture joint surfaces were measured. Next, 3D coordinates of joint surfaces were extracted with using the Geomagic software, and joint roughness was described using the mean variance of protrusion height and equidistant fluctuation angle, which were acquired through calculation. Stress-seepage coupling test was then conducted on the samples on a triaxial apparatus, and the effects of confining stress and water pressure on the permeability of single-fracture rock were investigated. On the basis of the relationship between the parameters in data fitting expression and the mean variance of protrusion height and equidistant fluctuation angle, the calculation formula of the permeability coefficient including joint roughness, confining pressure, and seepage pressure difference was derived.

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.

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