Nonlinear Strength Yield Index of Surrounding Rock Stability for Underground Opening

doi:10.3969/j.issn.1674-0696.2015.02.07

Abstract

Abstract: According to the analysis of surrounding rock yield index of the Mohr-Coulomb criterion and Drucker-Prager yield criterion, yield index (YI) is proposed based on I1 and J2. Both two methods are equivalent in the linear yield criterion, YI based on I1 is smaller than J2in nonlinear yield criterion, and YI based J2 is suggested. In view of the solution for generalized Hoek-Brown criterion exist mathematical difficulty, the generalized Hoek-Brown strength parameters are converted into the equivalent strength parameters, the yield evaluation of surrounding rock stability is further performed by substituting them into the YI expression of Mohr-Coulomb criterion. In addition, numerical experiments are conducted, and the results show that the law of equivalent plastic strain are similar to that of YI after tunnel excavation and support, the accuracy of YI is verified. YI of tunnel can show the degree of stress concentration and the interpretation law of surrounding rock safety state, describe more accurately the stress state of surrounding rock.

Key words: geotechnical engineering, stability of surrounding rock, yield index(YI), Hoek-Brown criterion

摘要： 通过分析Mohr-Coulomb和Drucker-Prager屈服准则现有的围岩屈服评价指标，提出了以I1，J2为基准的屈服评价指标。在线性屈服准则中两者是等价的，在非线性强度准则中，以I1为基准的屈服评价指标较小，建议采用以J2为基准的屈服评价指标。对于以J2为基准的广义Hoek-Brown准则的求解存在着数学上的困难，将其转换为等效强度参数代入Mohr-Coulomb准则屈服评价指标表达式，进而对围岩稳定性进行屈服评价。算例分析表明:隧道开挖支护后的等效塑性应变和屈服评价指标规律一致，验证了该屈服评价指标的正确性;隧道屈服评价指标可以直观的显示隧道应力集中程度及围岩安全状态的演绎规律，能够更准确的描述围岩受力状态。

关键词: 岩土工程, 围岩稳定性, 屈服评价指标, Hoek-Brown准则

CLC Number:

TU451

Wu Hengbin，Zhang Xuefu. Nonlinear Strength Yield Index of Surrounding Rock Stability for Underground Opening[J]. Journal of Chongqing Jiaotong University(Natural Science), 2015, 34(2): 28-32.

吴恒滨,张学富. 地下工程围岩稳定性的非线性强度评价指标[J]. 重庆交通大学学报（自然科学版）, 2015, 34(2): 28-32.

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