冻融循环作用下注浆裂隙岩体微观孔隙演化规律及剪切力学行为研究  

Study on micro-pore evolution law and shear mechanical behavior of grouting fractured rock mass under freeze-thaw cycle

作　　者：张嘉凡[1] 徐荣平 刘洋[1,2] 张慧梅 ZHANG Jiafan;XU Rongping;LIU Yang;ZHANG Huimei(Department of Mechanics,Xi'an University of Science and Technology,Xi¢an,Shaanxi 710054,China;Xi¢an ResearchInstitute of China Coal Technology and Engineering Group Crop,Xi¢an,Shaanxi 710054,China)

机构地区：[1]西安科技大学力学系,陕西西安710054 [2]中国煤炭科工集团西安研究院有限公司,陕西西安710054

出　　处：《岩石力学与工程学报》2022年第4期676-690,共15页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(12172280,41907259);陕西省自然科学基金重点资助项目(2020JZ-53)。

摘　　要：为研究冻融循环作用下注浆裂隙岩体的微观孔隙演化规律及其剪切力学响应,选用普通水泥(P型)、超细水泥(C型)及环氧树脂(H型)3种注浆固结体试样,进行冻融循环、核磁共振(NMR)及剪切试验,分析冻融循环过程中浆-岩界面层表观、微观孔隙结构变化特征及其剪切力学特性,研究宏微观多尺度注浆固结体破坏机制。结果表明:(1)随冻融循环次数增加3类试样均出现不同程度颗粒剥落、脱落及开裂现象,P型浆-岩界面层冻融劣化程度最为严重,其次为C型,H型表现最好;(2)3类试样浆-岩界面层核磁共振T;谱曲线演化趋势相近,且随冻融循环次数增加呈右移趋势,初始孔隙大小表现为P型>C型>H型,在冻融循环过程中,孔隙孔径表现出由微孔向介孔、介孔向大孔演化的特征。(3)浆-岩界面层的冻融劣化主要由内部水分在循环温度作用下的固液相变及迁移引起的,且注浆材料的不同对浆-岩界面层冻融劣化程度有较大影响。(4)3类试样整体剪切应力-应变曲线趋势接近,但剪切强度(τ;)和剪切刚度(K;)大小分别为H型试样最大,其次为C型,最小为P型,且3类试样τ;和K;均随冻融循环次数增加而降低。(5)注浆固结体的T;谱谱面积和剪切强度具有函数关系,以此为基础,得到不同冻融循环次数下基于微观孔隙演化规律的浆-岩界面层剪切破坏机制,即剪应力作用下,浆-岩界面层内部孔隙在尖端起裂并与相邻孔隙连接成微裂隙面,微裂隙面沿浆-岩界面层扩展形成宏观裂纹,最终导致注浆固结体沿浆-岩界面层的剪切破坏。研究结果为评价季冻区裂隙岩体注浆效果、提高岩体工程稳定性提供理论依据。In order to study the microscopic pore evolution law and shear mechanical response of grouting fractured rock mass under the action of freeze-thaw cycle,three kinds of grouting reinforcement body samples including ordinary cement(P-type),superfine cement(C-type) and epoxy resin(H-type) are selected for freezing cycles,nuclear magnetic resonance(NMR) and shear tests.On this basis,the apparent characteristics,microscopic pore structure and shear mechanical properties of the slurry-rock interface layer during the freeze-thaw cycle are analyzed,and the failure mechanisms of macroscopic and microscopic multi-scale grouting consolidation are studied.The results show that:(1) With increasing the number of freeze-thaw cycles,the three types of samples have different degrees of particle spalling,shedding and cracking.The freeze-thaw deterioration of the P-type slurry-rock interface layer is most serious,followed by C-type and H-type.(2) The evolution trends of NMR T;spectra at the slurry-rock interface layer of the three types of samples are similar and show a right-shift trend with increasing the number of freeze-thaw cycles.The initial pore size is P-type> C-type>H-type.In the process of freeze-thaw cycles,the pore size is characterized by the evolution from micropore to mesopore and from mesopore to macropore.(3) The freezing-thawing deterioration of the slurry-rock interface layer is caused by the solid-liquid phase transformation and migration of the internal water under the action of cyclic temperature,and the different grouting materials have a great influence on the freezing-thawing deterioration of the slurry-rock interface layer.(4) The overall shear stress-strain curves of the three types of specimens are similar,and the shear strength(τ;) and shear stiffness(K;) of three types of specimens decrease with increasing the number of freeze-thaw cycles.However,τ;and K;of H-type specimens are the largest,followed by C-type and P-type.(5) There is a functional relationship between the T;spectral area and the shear s

关 键 词：岩石力学 冻融循环 注浆固结体 浆-岩界面层 核磁共振 

分 类 号：TU45[建筑科学—岩土工程]