摘要
传统锚喷支护不能满足软岩隧道变形控制的要求,让压支护成为控制变形的重要手段。环向让压支护是在隧道环向设置让压装置,实现支护结构刚-柔-刚的特性。从隧道开挖-支护过程中能量转化的角度,阐明了环向让压支护的原理,运用结构力学的解析法分析影响支护结构变形的主要因素,利用有限元软件ABAQUS比较分析传统支护与环向让压支护力学特点。得出如下结论:初期支护属于典型的压弯构件,环向让压支护通过环向压力使得让压装置屈曲,与支护结构的内力相一致,既能实现一定的支护阻力,又通过周长的缩短调整围岩应力和围岩压力;环向让压装置应设置在弯曲应力较小处,并确保其抗剪切的刚度和承载力,应具备"强剪弱压"的特点;环向让压支护具有刚-柔-刚的力学特性,可以实现与高地应力软岩的流变特性相适应。
It is difficult for traditional bolt-shotcrete support to meet the requirements of deformation control in soft rock tunnel,therefore yielding support becomes an important means to control deformation.The circumferential yielding support sets up the yielding device in the circumferential direction of the tunnel in order to realize the rigid-flexible-rigid characteristics of the supporting structure.From the perspective of energy transformation in tunnel excavation-support process,the principle of circumferential yielding support is clarified in this paper.The main factors affecting the deformation of the support structure are analyzed using the analytical method of structural mechanics,and the mechanical characteristics of traditional support and circumferential yielding support are compared using the finite element software ABAQUS.The following conclusions are drawn:the initial support is a typical compression-bending member.The circumferential yielding support causes the yielding device to buckle through the circumferential pressure,which balances with the internal force of the support structure.It is hence possible to achieve a certain support resistance while controlling the surrounding rock stress by shortening the circumference.The circumferential yielding device should be set at places where the bending stress is relatively small.The shear stiffness and bearing capacity of the device should be ensured with the characteristics of"strong shear and weak compression".The circumferential yielding support has the mechanical characteristics of rigid-flexible-rigid,which can be adapted to the rheological characteristics of soft rock with high geo-stress.
作者
雷升祥
赵伟
LEI Sheng-xiang;ZHAO Wei(School of Civil Engineering,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;Key Laboratory Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu,Sichuan 610031,China;China Railway Construction Corporation Limited,Beijing 100855,China)
出处
《岩土力学》
EI
CAS
CSCD
北大核心
2020年第3期1039-1047,共9页
Rock and Soil Mechanics
基金
国家重点研发计划资助(No.2018YFC0808702,No.2018YFC0808706)
工程材料与结构加固福建省高校重点实验室开放基金(No.B170001-1)。
关键词
软岩隧道
大变形
环向让压支护
soft rock tunnel
large deformation
circumferential yielding support
