高径比对板岩单轴抗压强度的尺寸效应试验.doc

高径比对板岩强度尺寸效应研究 刘晓红(1.湖南理工学院，岳阳，41400)摘要：对的板岩试件进行了大量单轴抗压强度试验，获得了板岩强度试件高径比关系曲线二者间的经验依据标准试件与非标准试件强度值，经验公式非标准试件单轴抗压强度提供尺寸效应 关键词：板岩强度；尺寸效应；高径比；试验研究Experimental study on the uniaxial compressive strength size effect by the ratio of height to diameter of slate specimen LIU Xiao-hong, CHEN Gang, CHEN Ji-guang (Department of Construction Engineering of Hunan Institute of Science and Technology, Yueyang, Hunan 414000, China) Abstract：According to a lot of uniaxial compressive strength on different ratio of height to diameter of the slate specimen, 3 relation curves and empirical formulas between specimens strengthen and ratio of height to diameter are obtained. Based on the strength ratio of standard and non standard specimens, the concept of rock strength size effect coefficient is put forward, and relation curves between slate strength size effect coefficient and ratio of height to diameter are drawn, and empirical formulas of rock strength size effect coefficient are given for 3 different weathering degrees of slate. The results showed that, the bigger the rock strength is, the more obvious the size effect is. The empirical formulas in this paper provide convenient new way for the correction of slate uniaxial compressive strength of non standard specimen, and also provide reference for other types of rock. Keywords：slate strength；size effect；ratio of height to diameter；experimental study 0 引言 大量前人研究成果表明，岩石强度具有明显的尺寸效应强度不再一个常数，而是随尺寸的增大而减小[6]对煤岩单轴抗压强度尺寸效应的试验及理论研究表明：随着煤岩岩样高宽比的增加，其单轴抗压强度呈下降趋势，弹性模量呈上升趋势。张后全等[7]基于不同高径比的灰岩试件单轴抗压强度尺寸效应现象，从理论上分析了产生岩石强度尺寸效应的原因。尤明庆[8]等对大理岩单轴抗压强度进行了试件高径比的尺寸效应研究，发现其强度随高径比的增大而非线性减小。梁昌玉等[9]对花岗岩单轴压缩特性的尺寸效应进行了试验研究，分析了应变速率对尺寸效应的影响规律。张明等[10]通过数值模拟的方法研究了加载条件对岩石强度尺寸效应的影响规律。 岳阳地区岩层主要为泥质板岩，试件标准尺寸规定为圆柱体。笔者长期从事，在岩单轴抗压强度试件时，所取岩块厚度不够大取样量少或软弱、完整性差，标准高径比。 试验方选取2 mm以内，高径比在0.5-3.0之间变化，具体试验方案详见下表1。对于表1所示试验方案的特别要求：每一组试验所有27个有效试件均要求切取于同一大块岩体上；单轴抗压强度试验方法及仪器设备均应按相关规范要求进行。表1 试验方案试验 分组 序号 圆柱试件尺寸 平行试 件个数 试件 状态 高h/mm 直径d/mm 高径比h/d A组： 微风化 板岩组 A-1 25 50 0.5 3 饱和 A-2 35