胶结砾质土心墙坝应力变形及裂缝扩展研究  

Study on Stress Deformation and Crack Propagation of Rock-Fill Dam with Cemented Gravel Soil Core

作　　者：刘东海[1] 王静静 Liu Donghai;Wang Jingjing(Key Laboratory of Hydraulic Engineering Simulation and Safety,Tianjin University,Tianjin 300072,China)

机构地区：[1]天津大学水利工程仿真与安全国家重点实验室,天津300072

出　　处：《天津大学学报（自然科学与工程技术版）》2022年第8期783-791,共9页Journal of Tianjin University：Science and Technology

基　　金：国家自然科学基金资助项目(51979189).

摘　　要：心墙拱效应是威胁超高心墙堆石坝安全的一个重要因素.通常采用心墙掺砾来减弱拱效应,但即便是掺砾情况下超高砾质土心墙堆石坝往往仍存在较大的心墙拱效应,且过多掺砾易形成渗流通道,不利于大坝防渗.考虑向砾质土中加入固化剂来制备胶结砾质土心墙料,以提高其变形模量,减弱心墙拱效应.以西南某高堆石坝为例,对不同固化剂掺量下胶结砾质土心墙堆石坝开展应力变形有限元数值模拟,分析胶结砾质土心墙坝的应力、变形等性态;同时,采用扩展有限元法(XFEM)分别对心墙上、中、下3个部位预设的裂缝进行正常蓄水期及水位超坝顶两种工况下的裂缝扩展模拟,以分析固化剂掺量对胶结砾质土心墙裂缝扩展的影响.结果表明:心墙固化剂掺量的增加可有效减弱大坝心墙拱效应,改善心墙抗水力劈裂性能;坝体应力水平及位移变化率均随着固化剂掺量的增加而减小,在一定程度上避免坝体因剪应力过大或变形不协调而发生破坏;心墙上部预设裂缝更易发生扩展,固化剂的掺加可有效抑制心墙裂缝的扩展,避免形成渗流通道.可见,胶结砾质土可为超高堆石坝心墙坝料选择提供一种新的可能.The core wall arch effect is an important factor that threatens the safety of super-high core rockfill dam.Generally,gravel is added to the core wall to reduce the arch effect,but excessive gravel easily forms seepage passage,which is harmful to the dam seepage prevention.The addition of solidifier to gravel soil core wall is considered to increase its deformation modulus and reduce the core wall arch effect.Taking a high rockfill dam in southwest China as an example,a finite element numerical simulation of stress and deformation of the cemented gravel core wall rockfill dam with different amounts of solidifier was performed to analyze the dam’s stress and deformation.Meanwhile,the extended finite element method(XFEM)was used to simulate the crack growth of preset cracks on the upper,middle,and lower parts of the core wall under two conditions of normal storage period and water level over the dam crest.Thus,the influence of the solidifier content on the crack propagation of the cemented gravel soil core wall was studied.Results show that an increase of solidifier content can effectively reduce the arch effect and improve the hydraulic splitting resistance of core wall.The change rate of dam stress level and displacement decreases with the increase of solidifier content,avoiding dam damage due to excessive shear stress or inconsistent deformation to a certain extent.Preset cracks on the upper part of the core wall are more likely to expand.The addition of solidifier can effectively restrain the expansion of cracks on the core wall and avoid the formation of seepage passages.It can be seen that the cemented gravel soil provides a new possibility for the selection of core materials for super-high core wall rockfill dam.

关 键 词：胶结砾质土 心墙堆石坝 拱效应 水力劈裂 裂缝扩展 

分 类 号：TV49[水利工程—水工结构工程]