软板岩膨胀特性试验及微观机制分析  

Swelling characteristics test and micromechanism of soft slate

作　　者：左清军[1] 吴立[2] 袁青[2] 陆中玏[2] 李波[2] 

机构地区：[1]三峡大学三峡库区地质灾害教育部重点实验室,湖北宜昌443002 [2]中国地质大学(武汉)工程学院,武汉430074

出　　处：《岩土力学》2014年第4期986-990,997,共6页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.41274230);湖北省自然科学基金重点项目(No.2013CFA110);三峡大学科学基金项目(No.KJ20130048)

摘　　要：针对软板岩内部特殊的构造及其遇水膨胀的特点,以湖南省怀化芷江地区的板岩为例,选取14组岩样分别进行矿物成分、微观结构测试和侧向约束膨胀试验,研究软质板岩的膨胀特性及其微观机制。结果表明:软质板岩侧向约束膨胀率与吸水时间之间呈指数函数关系,在试验早期,侧向约束膨胀率随吸水时间的延长而增大,且增长速率较快,侧向约束膨胀率-吸水时间关系曲线较陡;在试验后期,侧向约束膨胀率趋于稳定,侧向约束膨胀率-吸水时间关系曲线由陡变缓。侧向约束膨胀率随着吸水率的增长呈乘幂函数关系增长,在试验早期增长较快,而后增长速率变小,直至最后趋于稳定。轴向膨胀率随轴向荷载的增加呈负对数函数减小,初期减小幅度较大,后期逐渐变低。结构面方向和试样轴向的夹角α在区间[0°,90°]之间变化时,极限侧向约束膨胀率随着夹角α的增大而减小。Fourteen groups of slate samples are selected to take the mineral ingredient and microstructure test and make the lateral restraint swelling experiment and study the swelling characteristics and micromechanism of soft slate, taking slate form Zhijiang, Huaihua in Hunan province for example and considering the internal structure of soft slate and its swelling characteristics with water. The results indicate that the relationship between the lateral restraint expansion ratio and water absorption time exhibits exponential function. In the early stage of test, the expansion ratio increases with the extension of water absorption time; the growth rate is fast; and expansion ratio-time relationship curve is relatively steep. At the end of the test, the expansion tends to be stable; and the shape of the curve becomes from steep to gentle. The relationship between the expansion ratio and water absorption rate exhibits the power function. In the early stage of test, the growth rate is fast with the increase of water absorption rate, and gradually becomes lower until it tends to be stable in the late period of the test. The axial expansion rate greatly decreases in the form of logarithmic function with the increase of the axial load in the early stage of test, and gradually becomes stable in the late period of the test. When the angle a between the soft slate structural plane and axial direction changing from 0° to 90°, the expansion ratio reduces with the increase of angle a.

关 键 词：软板岩 膨胀特性 微观机制 无量纲化 

分 类 号：TU45[建筑科学—岩土工程]