Numerical analysis on mechanical difference of sandstone under in-situ stress,pore pressure preserved environment at depth

Hongwei Zhou ¹Mingyuan Lu ²Heping Xie ³Wenhao Jia ⁴Ruidong Peng ⁵Yimeng Wang ²Bocen Chen ²Pengfei Jing²

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作者信息

1. School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China;State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology-Beijing,Beijing 100083,China
2. School of Energy and Mining Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China
3. State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resource and Hydropower,Sichuan University,Chengdu 610065,China;Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Institute of Deep Earth Sciences and Green Energy,College of Civil and Transportation Engineering,Shenzhen University,Shenzhen 518060,China;Shenzhen Key Laboratory of Deep Underground Engineering Sciences and Green Energy,Shenzhen University,Shenzhen 5180
4. School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China
5. State Key Laboratory of Coal Resources and Safe Mining,China University of Mining and Technology-Beijing,Beijing 100083,China;School of Mechanics and Civil Engineering,China University of Mining and Technology-Beijing,Beijing 100083,China
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Abstract

Deep in-situ rock mechanics considers the influence of the in-situ environment on mechanical properties,differentiating it from traditional rock mechanics.To investigate the effect of in-situ stress,pore pressure preserved environment on the mechanical difference of sandstone,four tests are numerically modeled by COMSOL:conventional triaxial test,conventional pore pressure test,in-situ stress restoration and recon-struction test,and in-situ pore pressure-preserved test(not yet realized in the laboratory).The in-situ stress restoration parameter is introduced to characterize the recovery effect of in-situ stress on elastic modulus and heterogeneous distribution of sandstone at different depths.A random function and non-uniform pore pressure coefficient are employed to describe the non-uniform distribution of pore pressure in the in-situ environment.Numerical results are compared with existing experimental data to validate the models and calibrate the numerical parameters.By extracting mechanical parameters from numerical cores,the stress-strain curves of the four tests under different depths,in-situ stress and pore pressure are compared.The influence of non-uniform pore pressure coefficient and depth on the peak strength of sandstone is analyzed.The results show a strong linear relationship between the in-situ stress restoration parameter and depth,effectively characterizing the enhanced effect of stress restoration and reconstruc-tion methods on the elastic modulus of conventional cores at different depths.The in-situ pore pressure-preserved test exhibits lower peak stress and peak strain compared to the other three tests,and sand-stone subjected to non-uniform pore pressure is more prone to plastic damage and failure.Moreover,the influence of non-uniform pore pressure on peak strength gradually diminished with increasing depth.

Key words

In-situ pore pressure-preserved environment/Numerical simulation approach/Deep in-situ rock mechanics/In-situ stress restoration and reconstruction

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基金项目

present work is supported by the National Natural Science Foundation of China(51827901)

present work is supported by the National Natural Science Foundation of China(52121003)

111 Project(B14006)

Yueqi Outstanding Scholar Program of CUMTB(2017A03)

Fundamental Research Funds for the Central Universities(2022YJSNY13)

出版年

2023

矿业科学技术学报(英文版)

中国矿业大学

矿业科学技术学报(英文版)

CSTPCDCSCDEI

影响因子：1.222

ISSN：2095-2686

参考文献量25

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