万福煤矿深厚表土层冻土力学性质试验研究

Experimental study on mechanical properties of frozen soil in deep soil of Wanfu coal mine

针对山东万福煤矿深厚表土采用冻结法施工的基础数据不足及工程经验欠缺等难题,采集万福煤矿的深部土样,开展深厚表土层冻土力学性能参数的测试与研究。结果表明:在本试验设计的冻结温度下,冻土试样的单轴抗压强度、三轴抗压强度、蠕变应力及冻胀力随着冻结温度的降低均呈现增大的趋势,同时深部表土层的冻土蠕变性质表现尤为明显,含水率和采样深度对冻结壁设计的影响不可忽略。通过对原状土单轴压缩试验、三轴抗压强度试验、单轴蠕变试验、冻胀试验等数据进行多元回归分析,综合考虑冻结温度、含水率和采样深度对冻土试样力学性能的影响,归纳得到的数学模型拟合程度高,相关性好,为深厚表土层冻结壁的设计和在不同地层地质条件下力学参数的确定提供了技术支撑。

Aiming at the problems of inadequate basic theory and lack of engineering experience in the construction of deep surface soil in Wanfu Coal Mine,it is required to collect the soil samples of the Wanfu deep well and to carry out the testing and analysis of the mechanical properties of the frozen soil.The results indicated:At the freezing temperature designed in this experiment,the uniaxial compressive strength,triaxial compressive strength,creep stress,and frost-heaving force of the frozen soil samples all show an increasing trend with the decrease of the freezing temperature.At the same time,the creep performance of frozen soil in the deep surface soil layer is particularly obvious.The influence of water content and sampling depth on the design of frozen wall can not be ignored.Therefore,according to the data of the single axis compression test,the three axis compressive strength test,the uniaxial creep test and the frost heave test,the multiple regression analysis is carried out,comprehensive consideration of the effects of freezing temperature,moisture content and sampling depth on the mechanical properties of frozen soil specimens,the mathematical models possess high degree of fit and good correlation.It provides technical support for the design of the frozen wall of deep surface layer and the determination of mechanical parameters under different geological conditions.