Seepage calculation method of loose rock mass under mining unloading

2020 ◽  
Vol 187 ◽  
pp. 154-162
Author(s):  
Fengjun Zhou ◽  
Jianhua Zhang
Author(s):  
Dan Huang ◽  
Xiao-Qing Li ◽  
Wen-Chao Song

In this study, grading of surrounding rock was based on rock mass basic quality (BQ) values according to the specifications in China. Numerical approach was to construct synthetic rock mass (SRM) model to represent the jointed rock mass, and obtain the strength of the rock mass. It represented intact rock by the bonded particle model (BPM), and represent joint behaviour by the smooth joint model (SJM) to construct the discrete fracture network (DFN). In the Hongtuzhang Tunnel, the micro properties of granite cores with different weathered degrees were determined by the validation process, and the calculation representative elementary volume (REV) of surrounding rock was 15 m×15 m. Five slightly weathered, three slightly to moderately weathered, and two moderately weathered granite surrounding rock mass models were established based on the probability distribution of joint sets in each borehole, the conversion BQ value was acquired according by the calculated strength of rock mass model. It was discussed the differences of surrounding rock grades between the geological survey method and the numerical calculation method, and then found that the geological survey report is higher than the numerical calculation method predicted. And the numerical calculation is consistent with the actual excavation of rock mass at borehole A1388.


2012 ◽  
Vol 249-250 ◽  
pp. 1099-1102
Author(s):  
Yi Sheng Huang ◽  
Jian Lin Li

Amending the normal stress over the slip surface based on the stress field by numerical analysis, applying the three-dimensional global limit equilibrium method to the stability analysis of tension-slackened rock mass in the right bank of Yagen hydropower station. Stability analysis shows that if do not take any measures, the loose rock mass stability can cater to the Specification demand, but some small sliders is in the limit state under the water and earthquake condition, if use the cutting slope and unloading scheme, the whole loose rock mass and the all small sliders can meet the Specification standard stability requirements.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Ye Yuan ◽  
Dengpan Qiao ◽  
Shibo Yu

Aimed at the problem to plug the main ore pass with the large collapse at Xingshan Iron Mine, the viscosity-time test and the heap perfusion test of cement-silicate grout in a loose rock mass are carried out. The relationship between the vertical diffusion distance of cement-silicate grout and setting time of grout is studied, and research results are applied to the design of plugging engineering of the main ore pass in -330 m. Based on the numerical simulation of the plugging structure and the long-term stress monitoring of the cable sensors, the stability of the plugging structure itself and the control for the movement of shafts nearby are comprehensively evaluated. The test results show that for a specific loose rock mass, the vertical diffusion distance of cement-silicate grout in the loose rock mass is a power function of grout setting time. Based on the design concept to plug the main ore pass with the large collapse using artificially constructed “bite-bonded arch,” the plugging design and construction procedures are proposed. A numerical model and long-term monitoring of cable stress show that the plugging structure is stable and has an obvious effect on the control movement of abutment shafts.


2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Ya-Qiong Wang ◽  
Cheng-Bin Ma ◽  
Zhi-Feng Wang

Landslide of loose rock mass at mountain tunnel exit occurs easily, and prediction of landslide position is one of the engineering problems to be solved urgently. Currently, existing and used prediction methods, such as field monitoring measurement, numerical analysis, nonlinear theories, and the geometric method, play a very important role and have their limitations. For example, there is a bigger difference between calculation mode by Wang et al.’s method and actual engineering situation; besides, there exists a relatively big discrepancy between the predicted and true position. Aiming to solve this problem, this article combined theoretical analysis and actual engineering situation to establish an optimal calculation mode. At the same time, this article re-deduced instability criteria based on the stress-transferring theory and examined the factors that influence solutions. The improved method can predict landslide position more accurately because the parameters (β, s, H, α, γ, c, φ, and T) related to the occurrence of landslide are taken into consideration. It is pointed out that landslide possibly occurs in the case of Δ ≥ 0 and Y ≤ 0. In addition, the equations s1 < s < s2 and 0 ≤ s ≤ H/sin α can determine landslide position accurately. The method is applied to two engineering examples, and the calculation results show that the deviations of predictive position from the actual landslide position are only 0.10% and 0.07%, respectively, indicating that prediction results are accurate and reliable. It is suggested that the proposed method is a useful tool in the design of tunnel engineering.


2019 ◽  
Vol 105 ◽  
pp. 01026
Author(s):  
Victor Tatsienko ◽  
Vyacheslav Gogolin ◽  
Inna Ermakova ◽  
Alexander Liskovets

This paper proposes a new method for calculating arch support with grouted space behind the support. The analysis of existing installations and methods for the calculation of frame supports was made. It has been established that the existing methods of frame parts calculation do not take into account the presence of grouted space behind the support. It is proposed to take into account the presence of the grouted layer in the space behind the support when it interacts with the rock mass. The formation of partially disturbed rock adjacent to the grouted layer is taken into account in the behaviour of rocks. In this method, the arch support is replaced with a ring support. The finite element method establishes the reduced dimensions of the ring support and its module of linear deformations, corresponding to these values of the arch support when its bearing capacity is lost. The scheme for calculating arch support ultimately boils down to considering the interaction of the support, the grouted layer, the zone of partially destroyed rocks and the rest of the mass of intact rocks in the hydrostatic field of rock pressure.


2010 ◽  
Vol 29-32 ◽  
pp. 1494-1498
Author(s):  
Chi Ai ◽  
Ji Nan Zhang ◽  
Guo Yong Liu

After the casing broken, under the action of internal and external pressure, the sidewall rock surrounding the fracture occurred damage and fragmentation and entered into the wellbore by the fracture, accumulation in the borehole. Due to the different sizes of rock mass damage fragmentation, formulation program for milling and sandwashing in workover was largely affected, the paper was started from velocity of elastic longitudinal wave, based on probability theory and the application of fractal geometry theory, a new calculation method of rock fractal dimension was established. The traditional theory of rock mass damage fragment distribution was enriched. The rock mass damage fragment distribution was more easily and more efficiently forecasted. And the reference frame of parameter design for casing-damaged well work over was provided, and guiding site-operation was quickly and effectively constructed.


CICTP 2020 ◽  
2020 ◽  
Author(s):  
Guoshuai Zang ◽  
Haizhu Lu ◽  
Guanglai Jin ◽  
Zhixiang Zhang

2015 ◽  
Vol 35 ◽  
pp. 132-135
Author(s):  
Matteo Fiorucci ◽  
Roberto Iannucci ◽  
Luca Lenti ◽  
Anotnella Paciello ◽  
Alberto Prestininzi ◽  
...  

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