袁大滩煤矿风化岩土体冻结热参数及单轴压缩试验研究

Experimental study on freezing thermal parameters and uniaxial compression of weathered rock and soil in Yuandatan coal mine

袁大滩煤矿岩土体风化严重,冻结井筒施工设计需要依据风化岩土体的冻结特性和力学参数。目前对于风化岩土体的冻结热参数及力学性质缺乏了解,通过风化岩土体钻孔取样,对细砂、黏土、细粒砂岩、粉砂岩和砂质泥岩试件进行了比热、导热系数、结冰温度等热参数和冻结单轴压缩方面的试验研究。结果表明:风化岩体的结冰温度低于风化表土,而导热系数大于风化土体,黏土的比热和容积比热最大。随温度降低,岩土体的抗压强度和弹性模量均逐渐增大,泊松比逐渐减小,但对岩土体泊松比的影响相对较小;温度对细砂、黏土和粉砂岩抗压强度的增幅相对较大,对细砂、黏土、细粒砂岩和砂质泥岩弹性模量的增幅相对较大;随温度降低,岩土体的抗压强度、弹性模量和泊松比变化幅度均呈加快趋势。

Considering the seriously weathered rock and soil of Yuandatan coal mine,the design of freezing shaft needs to be based on freezing characteristics and mechanical parameters.However,the current research on freezing thermal parameters and mechanical properties of weathered rock and soil is still not adequate.In this paper,by obtaining samples through drilling in the weathered rock and soil,the thermal parameters such as specific heat,thermal conductivity,freezing temperature and freezing uniaxial compression of fine sand,clay,fine sandstone,siltstone and sandy mudstone specimens were studied.The results indicate that the freezing temperature of the weathered rock mass is lower than that of the weathered topsoil,that its thermal conductivity is larger than that of the weathered soil,and the specific and volume specific heat of clay are the largest.With the decrease of temperature,the compressive strength and elastic modulus of rock and soil increases gradually,and its Poisson’s ratio decrease gradually.However,the effect of temperature on the Poisson’s ratio of rock and soil is relatively small.The increase in compressive strength of fine sand,clay and siltstone is relatively high while the increase of the elastic modulus of fine sand,clay,fine sandstone and sandy mudstone is also relatively large.With the decrease of temperature,the change in amplitudes of compressive strength,elastic modulus and Poisson’s ratio of rock and soil all tend towards upward speed.