Stability Analysis of Underground Caverns by Jointed Finite Element Method

2012 ◽  
Vol 238 ◽  
pp. 814-817 ◽  
Author(s):  
Ji Chang Wu ◽  
Yu Min Zhang ◽  
Hong Xia Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Fractured Rock ◽  
Deformation Characteristic ◽  
Collapse Mechanism ◽  
Fractured Rock Mass ◽  
Underground Caverns ◽  
Water Collection ◽  
Element Method

The jointed finite element method (JFEM) is used to analyze the deformation and failure characteristic of fractured rock mass and anchor reinforcement effect for the water collection shaft of the main power house of Dagangshan Hydropower Station. The results show that the JFEM not only simulates the actual rock mass structure very well, but also gives the reasonable simulation results for the common unstable rock mass. The JFEM may accurately simulate the major deformation characteristic and collapse mechanism, which is another effective way to analyze the stability of fractured rock mass. The on-site monitoring results show that the anchor reinforcement is effective for the water collection shaft

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.

Thermal Conductivity Test and Coupling Simulation of Heat-Transfer in Fracture Rock

2011 ◽  
Vol 382 ◽  
pp. 3-6
Author(s):  
Shu Guang Zhang ◽  
Yong Gang Yu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Finite Element ◽  
Temperature Field ◽  
Rock Mass ◽  
Fractured Rock ◽  
Coupling Model ◽  
Fluid Temperature ◽  
Fracture Rock ◽  
Fractured Rock Mass

In order to research thermal conductivity of fracture rock, fluid-heat coupling test and simulation are studied. Empirical equation of thermal conductivity is obtained and conductivity factor is ensured by test data. Based on the fluid-heat coupling model of heat-transfer, temperature field distribution of fracture rock is described. At the same time, the heat-transfer equation is discretized by using weighted residual Galerkin finite element. Combined with boundary condition and parameters, the temperature field in fractured rock mass is simulated by finite element method. The temperature of fractured rock mass under the action of the seepage is combined with the initial rock temperature, fluid temperature and the rate of the flow. Thermo-isoline is discontiguous at boundary of fracture, which shows that the seepage affects the distribution of temperature field. The change rate of temperture isoline is gradually reduced along the single fissure flow, therefore the rate of heat-transfer is decreased. The influence of fluid temperature to temperature distribution is small, but different fluid temperature obviously affects thermo-isoline.

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.

The Research on Application of Strength Reduction Finite Element Method in Stability Analysis of Weak Intercalated Rock Tunnel

2011 ◽  
Vol 255-260 ◽  
pp. 1926-1929
Author(s):  
Da Kun Shi ◽  
Yang Song Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Safety Factor ◽  
Slip Surface ◽  
Strength Reduction ◽  
Surrounding Rock ◽  
Stability Of Surrounding Rock ◽  
The Stability ◽  
Element Method

Based on geologic condition of one tunnel surrounding rock mass, systematic numerical tests had been carried out to study the stability of surrounding rock mass with different distributions of weak intercalated rock by the FEM software ABAQUS and strength reduction finite element method. Some quantificational results about the stability of surrounding rock mass were summarized. And the safety factor and latent slip surface were worked out. The stability of surrounding rock mass was judged by strength reduction finite element method. According to the analysis above, it’s known that the discrepancy of two rules is small; the safety factor is the lowest when weak intercalated rock in vault, and when at bottom, it’s higher than that of in vault. The conclusion can be used to guide the procedure of construction and ensure the safety.

scholarly journals Characterization of the disturbed zone in a large rock excavation for the Three Gorges Project

2001 ◽  
Vol 38 (1) ◽  
pp. 95-106 ◽  
Author(s):  
J H Deng ◽  
C F Lee ◽  
X R Ge
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Rock Mass ◽  
Elastic Modulus ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
Disturbed Zone ◽  
The Three Gorges Project ◽  
Element Method

Excavation in a rock mass leads to the perturbation of the stress regime, often creating a stress-relieved, locally weakened zone known as the disturbed zone. This paper presents the results of in situ studies that were carried out both in the central rock barrier (or separation block) between the shiplift and the temporary shiplock and in the northern slope of the permanent shiplock of the Three Gorges Project. The vertical extent of the disturbed zone was determined jointly by cross-hole seismic wave penetration testing and borehole elastic modulus testing, and the horizontal extent was assessed by monitoring and evaluating the deformation characteristics. Compared with the undisturbed rock mass, the P-wave velocity of the disturbed zone was reduced by 34–38% and the borehole elastic modulus by 12–31%. The reductions were caused by the opening of primary structural planes or the extension of apertures due to local sliding along the structural planes. In the disturbed zone, no newly formed fractured planes were found. The observed disturbed zone was compared with the tensile stress zones and the shear-damaged zones calculated by the finite element method. A rock reinforcement scheme was recommended and implemented.Key words: disturbed zone, mechanical properties, brittle rock mass, excavation, finite element method, reinforcement.

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