铁岭组中风化柱状叠层石灰岩强度确定概率方法

PROBABILITY METHOD FOR DETERMINATION OF POINT LOAD TEST STRENGTH OF MEDIUM WEATHERED COLUMNAR STROMATOLITES LIMESTONE AT XIAOYUSHAN MINE

研究区大量分布中风化柱状叠层石灰岩,岩石强度具有很强的变异性和区域性,而岩石强度是影响边坡稳定的重要因素。要进行边坡稳定性评价,就需要对研究区现场试验数据作为随机变量进行概率统计分析,获取可靠的岩石强度指标。本文通过对研究区内中风化柱状叠层石灰岩(t32)现场点荷载实验数据进行统计分析,利用x2检验进行拟和,得到岩石强度的概率密度函数和概率分布形式,抗压强度和抗拉强度均服从对数正态分布。在此基础上,结合相近岩性岩石强度的拟和结果,建立区内中风化柱状叠层石灰岩点荷载试验强度概率分布函数。运用Bayes估计推断区域内中风化柱状叠层石灰岩岩石点荷载强度,得到岩石抗压强度预测值为72.42 MPa,抗拉强度预测值为2.29 MPa,相对误差较小,样本信任度达到70%以上。该方法对于岩石强度估计是有效的,由该方法所得到的估计值对研究区边坡稳定性评价以及后期边坡治理都具有重要的实践意义。

The weathered columnar stromatolites are widely distributed in the study area and have a strong rock strength and the regional variability. The rock strength is the important factor for slope stability. Evaluation of slope stability needs to analyze the field test data as stochastic variable to obtain the reliable indicators of rock strength. This paper bases on the statistical analysis of the point load test data of medium weathered columnar stromatolites limestone in study area and uses the fitting of probability density function with the .2 check method. It draws the conclusion that probability distribution form of the rock strength. The compressive strength and tensile strength are subject to the lognormal distribution. This result is further combined with the fitting results of the strength of similar rock lithology. A a result, this paper establishes the probability distribution function for point load test strength of medium weathered columnar stromatolites limestone in the study area. The limestone point load strength was deduced with Bayes estimation. The predictive value of rock strength is obtained. The relative error is less and sampling confidence is over 70%. The tensile strength was 2.29 MPa, the compressive strength was 72.42 MPa. The method for the rock strength was estimated to be effective, the values obtained with the method had the important practical significance to evaluate slope stability and manage the slope.