川南地区典型砂岩强度特性分析

以四川宜宾市高县的典型砂岩为研究对象，进行基本物性试验、矿物成分分析、饱和与烘干两种状态下的点荷载和单轴抗压强度试验，分析含水状态对砂岩强度的影响和点荷载强度指数I_s(50)与单轴抗压强度UCS间的转换关系。结果表明:饱和状态下砂岩I_s(50)在0.89～1.36 MPa，均值1.14 MPa，UCS为19.98 MPa，烘干状态下I_s(50)在2.07～2.82 MPa，均值2.43 MPa，UCS为43.98 MPa；试样I_s(50) 与UCS在饱和后衰减比例基本一致，约55 %，工程实践中可利用点荷载强度了解其软化特性；公路沿线典型砂岩建议采用UCS=17.53 I_s(50)作为两种强度之间的转换关系。

Analysis of Strength Characteristics of Typical Sandstone in Southern Sichuan

Taking the typical sandstones from Gao Country of Yibin in Sichuan as the research object, the basic physical properties test and mineral composition analysis have been carried out, and the point load test and uniaxial compressive strength test under two states of saturation and drying have been proceeded as well. The influence of moisture state on the strength of sandstone and the conversion relationship between the point load strength index I_{s (50)} and the uniaxial compressive strength UCS have been analyzed. The result shows that I_{s (50)} of sandstone in the saturated state fluctuates within the range of 0.89 ~1.36 MPa, with an average value of 1.14 MPa and UCS of 19.98 MPa; I_{s (50)} in the dry state is between 2.07~ 2.82 MPa, with an average of 2.43 MPa, UCS is 43.98 MPa. The attenuation ratio of the sample I_{s (50)} and UCS after saturation is basically the same, about 55 %. In engineering practice, the point load strength can be used to understand its softening characteristics. For typical sandstones along the highway, it is recommended to use UCS = 17.53 I_{s (50)} as the conversion relationship between the two intensities.