为实现软岩原位旋转触探,以达到连续、快速、准确地确定软岩力学参数的目的,必须清楚软岩的力学参数与触探时荷载参数的内在关系.以砌块、特级石膏A、特级石膏B和模具石膏试样来模拟单轴抗压强度不超过15 MPa的软岩,采用成孔直径相同的角片式探头及锥柄式标准麻花探头,在相同运行参数下,对这几种类型试样进行旋转触探及单轴抗压和抗剪试验,获得探头上的轴向压力和扭矩及试样的抗压强度、弹性模量和抗剪强度值.并根据探头上切刀对试样加载方式与试样的单轴抗压和抗剪试验中的加压板加载方式的相似性,从理论上建立触探时轴向压力、扭矩与试样的抗压强度、弹性模量、黏聚力及内摩擦角的数学模型,即2套参数间的内在理论关系:触探时试样局部处于体积破坏阶段时,轴向压力、扭矩和试样的抗压强度、黏聚力及内摩擦角有关,但与弹性模量无关,且轴向压力、扭矩随着抗压强度、黏聚力的增加而呈线性增加;而处于研磨阶段时,轴向压力、扭矩和试样弹性模量、黏聚力及内摩擦角有关,与抗压强度无关.%In order to carry out the in-situ rotary penetration test for determining the mechanical parameters of soft rock quickly and accurately, the intrinsic relationship between mechanical parameters of soft rock and load parameters of rotary penetration test should be known. The soft rock with uniaxial compression strength less than 15 MPa is simulated by the building block, gypsum A, gypsum B and mould gypsum samples. The uniaxial compressive test, shear test and rotary penetrometer test with two kinds of probes with the same diameter of pore-forming are carried out under the same experimental conditions. The axial force and torque of the probe, and the compression strength, Young's modulus and shear strength of the sample are obtained. In the light of the similarity between cutter's loading mode in rotary penetrometer test and plate's loading modes in uniaxial compressive test and shear test, the mathematical model of load parameters in rotary penetration test and mechanical parameters in uniaxial compressive test is established theoretically, which is the intrinsic relationship of the two kinds of parameters. When the sample is at the stage of local volume damage during penetration test, the axial force and torque are not only related to the compression strength, cohesion and internal friction angle,except Young's modulus, but also linearly increasing with the compression strength and cohesion. When the sample is at the stage of grinding damage, the axial force and torque are related to the Young's modulus, cohesion and internal friction angle except the compression strength.
展开▼
