摘要
红层软岩透水性弱、亲水性强,受含水量和水热(温度和降雨)变化影响极易发生软化崩解,给红层软岩地区工程建设和地质环境带来挑战。为研究不同含水量和多种水热试验工况下红层软岩的崩解特征和微观机理,以川西金堂县和中江县两处开挖红层软岩边坡工程为依托,利用自制降雨装置和温控设备,开展不同梯度初始含水量红层软岩在多种水热试验工况下的循环崩解试验。从红层软岩宏观形貌演变、微观结构及矿物组成、崩解系数、R值(崩解质量损失率)和崩解后颗粒分析5个方面对红层软岩崩解情况进行了研究,试验结果表明:红层软岩宏观形貌演变特征与微观结构变化及矿物差异存在一定的对应关系;黏土矿物的含量是红层软岩发生崩解的主要内因且与崩解呈正相关关系;崩解程度与初始含水量及水热效应联系密切;两处红层软岩R最小/大值差距明显,分别为0.22%、0.05%和1.63%、2.17%;粒径分布对红层软岩的崩解程度具有较好的评价作用,崩解越强烈,大颗粒越少,小颗粒越多,小颗粒更集中于0.075~0.5 mm之间。崩解系数、R值和最终粒径分布曲线可以很好地结合起来对红层软岩的崩解进行量化分析,并与微观结构及矿物差异相联系解释红层软岩的崩解演变特征。研究成果可为金堂、中江及其他红层软岩地区的工程建设和地质评价提供一定参考。
The red-bed soft rock has weak water permeability and strong hydrophilicity,and is prone to softening and disintegration under the influence of water content and hydrothermal(temperature and rainfall)changes,which brings challenges to engineering construction and geological environment in red-bed soft rock areas.This paper studies the disintegration characteristics and microscopic mechanism of red-bed soft rock under different water contents and various hydrothermal test conditions.It uses samples from the red-bed soft rock excavations of the slopes of the Jintang and Zhongjiang sections in Western Sichuan.It uses a self-made rainfall device and temperature control equipement to carry out the cyclic disintegration tests on samples with different initial water contents under multi-hydrothermal test conditions.Red-bed soft rock disintegration is studied from five aspects including macro-morphological evolution,micro-structure and mineral difference,disintegration coefficient,R value(disintegration mass loss rate),and particle analysis after disintegration.The test results show a certain interaction between the macroscopic morphology evolution characteristics of the red-bed soft rock and the changes in micro-structure and mineral differences.The clay mineral content can be the main internal cause of disintegration of red-bed soft rock and is positively correlated with disintegration.The degree of disintegration is closely related to initial water content and hydrothermal effect.The R values of the two red-bed soft rock samples range from 0.22%to 1.63%and 0.05%to 2.17%.The particle size distribution is a good indicator for the degree of disintegration of a red-bed soft rock.Higher disintegration is characterized by fewer large and more small particles,and the small particles are mostly concentrated between 0.075 and 0.5 mm.A combined analysis of the disintegration coefficient,R value,and final particle size distribution curve can be effective for quantitatively assessing the disintegration and explaining the disintegration evolution characteristics of red-bed soft rock in conjunction with micro-structure and mineral differences.The research results can provide a certain reference for the engineering construction and geological evaluation of Jintang,Zhongjiang,and other red-bed soft rock areas in Sichuan.
作者
刘凤云
谢飞
邱恩喜
罗怀瑞
王知深
万旭升
LIU Fengyun;XIE Fei;QIU Enxi;LUO Huairui;WANG Zhishen;WAN Xusheng(School of Civil Engineering and Geomatics,Southwest Petroleum University,Chengdu 610500,China)
出处
《工程地质学报》
CSCD
北大核心
2022年第5期1597-1608,共12页
Journal of Engineering Geology
基金
国家自然科学基金资助项目(资助号:42071087)
西南石油大学启航计划资助项目(资助号:2021QHZ003)
四川省科技厅项目(资助号:2020YJ0416).
关键词
红层软岩
崩解特征
微观机理
温度
降雨
梯度初始含水量
Red-bed soft rock
Disintegration characteristics
Microscopic mechanism
Temperature
Rainfall
Different initial water contents
