基于悬臂梁流变试验的倾倒变形力学特性分析  

Mechanical Characteristics Analysis of Toppling Deformation Based on Rheological Tests for Cantilever Beam

作　　者：郑达[1] 苏杭 庞波[1] ZHENG Da;SU Hang;PANG Bo(Sate Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]成都理工大学地质灾害防治与地质环境保护国家重点实验室,四川成都610059

出　　处：《西南交通大学学报》2020年第5期1001-1008,共8页Journal of Southwest Jiaotong University

基　　金：国家重点研发计划(2018YFC1504905);国家自然科学基金(41772317);成都理工大学地质灾害防治与地质环境保护国家重点实验室自主研究课题(SKLGP2015Z015)的资助.

摘　　要：弯曲倾倒变形本质是岩层所发生的弯曲流变变形,为了阐明其时效特点与力学特性,首先对反倾层状斜坡进行受力分析,将岩层某点的受力简化为自重应力与水平侧应力;其次在该受力条件下,进行了悬臂梁弯曲流变试验,将岩层悬臂式弯曲流变模型概化为4个阶段:瞬时变形阶段、衰减蠕变阶段、稳态蠕变阶段、加速蠕变阶段.基于上述的试验和分析,推导出悬臂梁弯曲流变的本构方程;并选取岩梁发生倾倒变形时极限位置处应变为0,对本构方程进行求解得出倾倒变形发育的极限深度;以悬臂梁倾倒折断时应变加速度等于稳态蠕变的上限加速度为求解条件,得出岩梁的倾倒折断深度.Curved toppling deformation is essentially the rock rheological deformation.In order to clarify its time-dependent characteristics and mechanical properties,the force analysis of anti-dip stratified slope is conducted,in which the force at a certain point of the rock layer is simplified as the gravity stress and horizontal stress.Then,the rheological tests of the bending cantilever beam are performed under this stress condition.The rheological model of the bending cantilever for rock strata is generalized as four stages:instantaneous deformation,attenuated creep,steady creep and accelerated creep.Based on the above tests and analysis,the constitutive equation for the rheological deformation of the bending cantilever beam is deduced.Through the calculation of the equation,assuming that the strain at the position of the ultimate toppling deformation of rock beam is zero lead to the ultimate depth of the toppling deformation.Given that as the beam breaks the strain acceleration is equal to the upper limit acceleration of the steady creep,the toppling fracture depth can be obtained.

关 键 词：倾倒变形 力学特性 悬臂梁流变试验 倾倒发育深度 倾倒折断深度 

分 类 号：TU[建筑科学]