南宁盆地软硬水平互层泥岩强度特性分析

为研究软硬水平互层泥岩的基本物理力学性质、强度特性,选取南宁盆地某典型泥岩层,通过建立水平互层泥岩模型,进行了物理力学试验、单轴抗压强度试验、三轴剪切试验、天然状态下岩石抗剪断强度试验以及现场标准贯入试验研究,着重考察了互层泥岩强度变化规律与物理力学特性的影响因素,结果表明:①互层泥岩强度低,强度变异大,天然状态下的单轴抗压强度为1.0～7.0 MPa,饱和单轴抗压强度为0.4～1.3 MPa。岩石在长期浸泡下,强度将折减约75%。②岩相变化大,裂隙发育,具有吸水膨胀失水收缩,并极易软化,水稳定性极差。③抗扰动性能差,无法准确划分风化带,具有较高的超固结特性。

Analysis on the strength properties of the mudstone with soft-hard alternant strata in Nanning basin

In order to analyze the physical and mechanical properties of mudstone with soft-hard alternant strata,a typical mudstone layer in Nanning basin was chosen,and the interbedded mudstone models were built.The physical and mechanical tests,such as the uniaxial compressive strength test,the triaxial test and anti-shear strength test were carried out.The experimental study focused on the physical and mechanical properties and the strength variation law.The results of the tests show that ①the strength of interbedded mudstone is low.Its uniaxial compressive strength is from 1.0~7.0 MPa under natural situation and 0.4~1.3 MPa under saturation situation.After a long-term immersion in water,the strength reduces approximately 75%.②The lithofacies of the mudstone changes sharply,and fracture develops.And it has the following properties: swell-shrink characteristics,easy to be soften,bad water stability.③The anti-disturbance performance of the mudstone is poor,and its weathered zone can not be accurately classified.The mudstone is over-consolidated.