盐度-温度对内蒙古砒砂岩断裂行为耦合作用机理  

Coupling mechanism of salinity and temperature on fracture behavior of soft sandstone in Inner Mongolia

作　　者：陈立超 王生维[2] 吕帅锋 CHEN Lichao;WANG Shengwei;L Shuaifeng(School of Resources and Environmental Engineering,Inner Mongolia University of Technology,010051 Hohhot,China;Faculty of Earth Resources,China University of Geosciences,430074 Wuhan,China)

机构地区：[1]内蒙古工业大学资源与环境工程学院,呼和浩特010051 [2]中国地质大学(武汉)资源学院,武汉430074

出　　处：《应用力学学报》2024年第5期1065-1074,共10页Chinese Journal of Applied Mechanics

基　　金：国家科技重大专项资助项目(No.2016ZX05067001-007);内蒙古自治区科技计划资助项目(No.2020GG0317)。

摘　　要：低温、矿化流体耦合下砒砂岩断裂力学特征对于内蒙古黄河岸坡岩体稳定性具有关键影响。利用半圆盘三点弯曲加载(semi-circular bending,SCB)对内蒙古准格尔旗砒砂岩在常温、低温条件下断裂行为进行试验研究,研究表明:相同盐度下液氮制冷后砒砂岩试样断裂载荷和断裂韧度显著下降,同等温度下试样断裂载荷和断裂韧度随浸泡流体盐度增大线性升高;液氮制冷后砒砂岩试样断裂全程能耗显著低于常温条件下试样,随浸泡流体盐度增加砒砂岩试样断裂能耗呈指数上升;液氮制冷后砒砂岩试样断裂速率远高于常温试样,随盐度增加砒砂岩断裂速率呈现出对数下降趋势;砒砂岩试样断裂韧度、断裂功及断裂速率损伤变量随盐度增大趋近于零,盐度对本区砒砂岩断裂行为影响显著。结合试样断口分析认为常温下砒砂岩内部盐度增大形成结晶(盐敏)效应提升了岩石在外载下的断裂效率,而低温环境砒砂岩内部含盐度增加反而削弱了冰劈效应。The fracture characteristics of soft sandstone under the coupling of low temperature and mineralized fluid have a key influence on the stability of the rock on the bank slope of the Yellow River in Inner Mongolia.The three-point loading is used to test the fracture behavior of soft sandstones in Jungar county,Inner Mongolia,under the conditions of room temperature(RT)and low temperature(LT).The results showed that the fracture load and fracture toughness of the soft sandstone samples decreased significantly after liquid nitrogen refrigeration under salt water immersion,and the fracture load and fracture toughness of the samples increased linearly with the increase of salinity at the same temperature.The energy consumption of the samples fractured after liquid nitrogen refrigeration was significantly lower than that of the samples at room temperature,and the fracture energy consumption of the samples increased exponentially with the increase of salinity.The fracture rate showed a logarithmic downward trend;the damage variables of fracture toughness,fracture work and fracture rate of the samples approached zero with the increase of salinity,and the salinity significantly affected the fracture behavior of the soft sandstone in this area.Combined with the fracture morphology of the samples,it is believed that the increase of the salinity of the soft sandstone at room temperature can form a crystallization(salt-sensitive)effect,which improves the fracture efficiency of the rock under loading,while the increase in the salinity in the soft sandstone at low temperature weakens the ice-splitting effect.

关 键 词：砒砂岩 断裂韧度 含盐流体、低温环境 SCB断裂试验 岸坡稳定性 内蒙古黄河段 

分 类 号：TU45[建筑科学—岩土工程]