Analytical Model for Stand-up Time of Rock Mass Surrounding Tunnel with Consideration of Softening Effect

被引：0
|
作者：
Wu J. [1 ]
Ren S. [1 ]
Fan J. [1 ]
Chen J. [1 ]
Liu W. [1 ]
Deng G. [1 ]
Yuan X. [1 ]
机构：
[1] State Key Lab. of Coal Mine Disaster Dynamics and Control, Chongqing Univ., Chongqing
来源：
Ren, Song (rs_rwx@cqu.edu.cn) | 2017年 / Sichuan University卷 / 49期
关键词：
Active span; Gypsum rock; Rock mass classification; Softening; Stand-up time; Tunnel stability;
D O I：
10.15961/j.jsuese.201600338
中图分类号：
学科分类号：
摘要：
The existing analytical solution of stand-up time neglected the softening effect of underground water, which resulted in overestimating the surrounding rock quality.This paper focused on the softening effect of water on stand-up time for the gypsum rocks with typical softening characteristics.The research method combined the softening test results of gypsum with the axisymmetric circular tunnel elastic theory.Firstly, the softening test of gypsum with different soaking time was carried out;thus, the absorption, elasticity modulus and Poisson's ratio changing over soaking time were obtained, respectively.The integrality index and water content coefficient were introduced into the quantitative relationship between the elasticity modulus and the soaking time and that between the Poisson's ratio and the soaking time; thus, the softening equation of mechanical parameter of rock mass was obtained.Then, based on the elastic solution of axisymmetric circular tunnel and the influence of tunnel face, the displacement formula of tunnel free face without supporting effects was developed.Then, the softening equation of mechanical parameter of rock mass was embedded into this displacement formula;thus, the displacement solution of free face considering softening effects was obtained.At last, the analytical model for stand-up time of rock mass surrounding tunnel with consideration of softening effect was established by introducing the active span and the critical displacement value into this displacement solution.This model takes into consideration the engineering features of rock mass, the mechanical performance of rock, and the softening behavior of rock.Moreover, it is able to show the relationship between the stand-up time and the active span.This model was further investigated by self-consistent analysis, which showed that the variation rule of each parameter accorded with actual situation and the self-consistency was met.This model was employed for the Lirang tunnel, which indicated that it is practical for in-site application. © 2017, Editorial Department of Advanced Engineering Sciences. All right reserved.
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页码：68 / 75
页数：7
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