高温作用后三种岩石物理力学参数与耐磨性相关性研究

Study on the correlation between physical and mechanical parameters of three types of rocks and resistance after high temperature

在TBM掘进过程中,TBM刀盘会与岩石剧烈摩擦产生不同程度的摩擦热,使TBM刀盘温度升高。【目的】为了研究高温处理后岩石物理力学参数与耐磨性之间的相关性,提出岩石物理力学参数与CAI值预测模型,利用岩石物理力学参数指标来预测岩石耐磨性,同时探究岩石CAI值随温度变化规律。【方法】以花岗岩、砂岩和大理岩三种岩性为例,对不同温度作用后的岩石分别开展Cerchar磨蚀试验和岩石物理力学测试,分别获得三种岩石的CAI值、密度、里氏硬度、波速、孔隙度、导热系数、抗拉强度和单轴抗压强度,然后,基于线性回归方法提出岩石物理力学参数与CAI值预测模型。【结果】结果显示:(1)高温处理后岩石物理性质方面,里氏硬度、纵波波速与CAI值之间相关性较好,花岗岩、砂岩、大理岩里氏硬度与CAI值相关系数R~2分别为0.944、0.714、0.885,三种岩石纵波波速相关系数R~2分别为0.925、0.835、0.891。岩石孔隙度与CAI值之间相关性很低,花岗岩和砂岩相关系数R~2分别只有0.171、0.657。(2)高温处理后岩石力学性质方面,岩石抗拉强度、单轴抗压强度与CAI值相关性很好,花岗岩、砂岩、大理岩抗拉强度与CAI值相关系数R~2分别为0.874、0.888、0.950,岩石单轴抗压强度相关系数R~2可高达0.962、0.996、0.877。【结论】结果表明:(1)高温作用后,岩石物理力学性质与耐磨性均随着温度升高而降低,且下降幅度因岩石类型存在很大差异,原因在于导热系数存在明显不同,因而影响高温作用下岩石物理力学性质与耐磨性变化规律。(2)在高温作用后岩石物理力学参数与CAI值之间相关性评价研究中,岩石力学指标与CAI值的相关性模型明显优于物理指标与CAI值的相关性模型。在物理指标与CAI值的相关性模型中,纵波波速最好,而孔隙度较差;力学指标模型中,抗压强度要略优于抗拉强度。

During the TBM digging process,the TBM cutter plate will produce different degrees of friction heat from the violent friction with the rock,which will increase the temperature of the TBM cutter plate.[Objective]In order to study the correlation between rock physical mechanical parameters and wear resistance after high temperature treatment,we propose a prediction model of rock physical mechanical parameters and CAI,and utilize rock physical mechanical parameter indexes to predict rock wear resistance,while exploring the change rule of rock CAI with temperature.[Methods]In this paper,taking granite,sandstone and marble as examples,we carry out cerchar abrasion test and rock physics and mechanics test on the rocks after different temperatures,and obtain the CAI,density,Leeb hardness,wave velocity,porosity,thermal conductivity and other physical parameters of the three kinds of rocks,and obtain the tensile strength,uniaxial compressive strength and other mechanical parameters.Finally,the prediction model of rock physico-mechanical parameters and CAI values is proposed based on linear regression method.[Results]The result show that:(1) Regarding the physical properties of the rocks after high-temperature treatment,the correlation between the Leeb hardness,longitudinal wave velocity and CAI is good,and the correlation coefficients of R~2 between the Leeb hardness and the CAI of granite,sandstone and marble are 0.944,0.714 and 0.885 respectively,and the correlation coefficients of R~2 of the longitudinal wave velocity of three kinds of rocks are 0.925,0.835 and 0.891 respectively.The correlation between rock porosity and CAI is very low,with correlation coefficients R~2 of only 0.171 and 0.657 for granite and sandstone,respectively.(2) With regard to the mechanical properties of rocks after high-temperature treatment,the tensile strength and uniaxial compressive strength of rocks correlate well with the CAI,and the correlation coefficients R~2 of the tensile strength of granite,sandstone and marble with the CAI,are 0.874,0.888 and 0.950,respectively,and the correlation coefficients R~2 of the uniaxial compressive strength of rocks can be as high as 0.962,0.996 and 0.877.[Conclusion]The result indicate that:(1) After high temperature action,the physical and mechanical properties of rock and wear resistance are reduced with the increase in temperature,and the decline in the magnitude of the rock type there is a big difference,the reason is that there is a significant difference in the coefficient of thermal conductivity,which affects the change rule of the physical and mechanical properties of the rock and wear resistance under the action of high temperatures.(2) In the evaluation of the correlation between rock physical and mechanical parameters and CAI after high temperature,the correlation model between rock mechanical index and CAI is obviously better than the correlation model between physical index and CAI.In the correlation model between physical indexes and CAI,the longitudinal wave velocity is the best,while the porosity is worse;in the model of mechanical indexes,the compressive strength is slightly better than the tensile strength.