基于时效变形的脆性围岩最优支护时机研究
发布时间：2018-10-09 15:35
【摘要】：现代地下工程支护结构设计的基本指导思想是按照"新奥法"原理,强调通过适时加固围岩,使得围岩成为承载结构的主体。但是对于支护时机的掌握,目前仍然缺乏可靠的理论和公式的指导,只能根据现场监测信息和经验判断来确定。提出脆性围岩的"适时支护",是指在围岩达到弹性极限应变而破坏之前进行支护,即在时效变形作用下,围岩应力处于本构关系弹性段后段,但是还没有进入软化的非稳定段。基于这一思想以及地下工程时效变形特征,提出了最优支护时机的近似计算公式。研究表明:最优支护时机与围岩收敛时间、围岩强度应力比、开挖后应力以及支护围压相关。由于围岩应力处处不同,可以由公式计算得到顶拱、边墙等不同部位的最优支护时机,从而指导支护设计。研究对长期困扰地下工程界的脆性围岩最优支护时机问题提出了一种理论方法。
[Abstract]:According to the principle of "New Austrian method", the basic guiding idea of modern underground engineering supporting structure design is to strengthen the surrounding rock in time and make the surrounding rock become the main body of the bearing structure. However, there is still a lack of reliable theory and formula to guide the timing of support, which can only be determined by field monitoring information and empirical judgment. It is put forward that the "timely support" of brittle surrounding rock means that the surrounding rock is supported before the rock reaches the elastic limit strain, that is, under the action of aging deformation, the stress of surrounding rock is in the back of the elastic segment of constitutive relation, but it has not entered the unsteady section of softening. Based on this idea and the time-dependent deformation characteristics of underground engineering, an approximate formula for calculating the optimal supporting time is put forward. The results show that the optimal supporting time is related to the convergence time of surrounding rock, the ratio of strength and stress of surrounding rock, the stress after excavation and the confining pressure of support. Because the stress of surrounding rock is different everywhere, the optimal supporting time of different parts such as top arch and side wall can be obtained by formula calculation, so as to guide the design of support. In this paper, a theoretical method is proposed to solve the problem of the optimal supporting time of brittle surrounding rock, which has been puzzling the underground engineering circle for a long time.
【作者单位】： 四川大学水利水电学院水力学及山区河流开发与保护国家重点实验室;中国电建集团成都勘测设计研究院有限公司;四川大学灾后重建与管理学院;
【分类号】：TU45
，
本文编号：2259854
[Abstract]:According to the principle of "New Austrian method", the basic guiding idea of modern underground engineering supporting structure design is to strengthen the surrounding rock in time and make the surrounding rock become the main body of the bearing structure. However, there is still a lack of reliable theory and formula to guide the timing of support, which can only be determined by field monitoring information and empirical judgment. It is put forward that the "timely support" of brittle surrounding rock means that the surrounding rock is supported before the rock reaches the elastic limit strain, that is, under the action of aging deformation, the stress of surrounding rock is in the back of the elastic segment of constitutive relation, but it has not entered the unsteady section of softening. Based on this idea and the time-dependent deformation characteristics of underground engineering, an approximate formula for calculating the optimal supporting time is put forward. The results show that the optimal supporting time is related to the convergence time of surrounding rock, the ratio of strength and stress of surrounding rock, the stress after excavation and the confining pressure of support. Because the stress of surrounding rock is different everywhere, the optimal supporting time of different parts such as top arch and side wall can be obtained by formula calculation, so as to guide the design of support. In this paper, a theoretical method is proposed to solve the problem of the optimal supporting time of brittle surrounding rock, which has been puzzling the underground engineering circle for a long time.
【作者单位】： 四川大学水利水电学院水力学及山区河流开发与保护国家重点实验室;中国电建集团成都勘测设计研究院有限公司;四川大学灾后重建与管理学院;
【分类号】：TU45
，
本文编号：2259854
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