深部岩石原位保温取心保温材料物理力学特性研究

Physical and mechanical properties of thermal insulation materials for in-situ temperaturepreserved coring of deep rocks

高温影响深部煤炭资源开采等工程活动,而传统陆地硬岩取心方法没有保温措施,忽略了温度对岩石物理力学性能的影响,导致获得的参数失真,影响深部煤炭等资源安全高效开采。为攻关深部岩石保温取心技术,提出采用环氧树脂基空心玻璃微珠材料作为保温材料应用于保温取心设备。开展了材料的物理、力学性能测试,结果表明:随微珠含量增加,保温材料导热系数呈显著下降趋势,但其力学性能出现弱化;同时,不同强度类型微珠含量增大时,保温材料力学性能降低,由于荷载承担对象的变化,会在不同体积分数处出现拐点;材料保温性能与强度是一对矛盾体,随微珠增加呈现出博弈竞争规律。为定量评价保温材料性能,定义了保温材料强度导热比,发现S60HS微珠体积分数为30%、40%、50%时的保温材料综合强度导热比分别为1.796、1.719、1.737,优于其他同类型材料,初步确定可以作为深部岩石取心保温材料。试验结果为深部岩石保温取心提供可能,进而为深部煤炭等资源开采提供支撑。

High temperature affects deep coal mining and other engineering activities.However,conventional coring methods for terrestrial hard rocks lack temperature-preserved measures,ignoring the effects of temperature on the physical and mechanical properties of rocks.Consequently,the parameters obtained are subjected to distortion,affecting the safe and efficient mining of resources such as deep coals.To make breakthroughs in the development of in-situ temperature-preserved coring technologies for deep rocks,this study proposed using the hollow glass microsphere/epoxy resin(HGM/EP)as thermal insulation materials and the physical and mechanical properties.The results are as follows:(1)With an increase in the HGM content,the thermal conductivity of the thermal insulation materials showed a significant downward trend,and the mechanical properties of the materials weakened.(2)The increase in the content of HGM with different strengths led to changes in the load-bearing objects.As a result,inflection points occurred at different volume fractions when mechanical properties decreased.(3)There is a contradiction between the thermal conductivity and strength,which compete with each other as the HGM content increases.To quantitatively evaluate the performance of thermal insulation materials,this study defined the strength-to-thermal conductivity ratio,discovering that thermal insulation materials with 30%,40%,and 50%volume fractions of S60HS HGM had comprehensive strength-to-thermal conductivity ratios of 1.796,1.719 and 1.737,respectively.These materials,outperforming similar materials,were preliminarily determined as thermal insulation materials for deep rock coring.The test results of this study make it possible to achieve in-situ temperature-preserved coring of deep rocks,further supporting the mining of resources such as deep coals.