Research On Rupture Mechanisms Of Coal Measures Sandstone Under High Temperature And Impact Load

Three-high-one-disturbance, which means high earth temperature, the highcrustal stress, the high karst water and strong mining disturbance, is the complex andextreme environment the rock should face when mining in deep, which brings greatchallenge-subject to coalmine safety production. Compared with normal static load,there are completely differences on mechanical properties and failure mechanism ofrock in complex mechanical environment, which are high temperature and high strainrate. Therefore, it is great influence on high-efficient mining production, which makesanalyzing on rock mechanical properties, damage evolution and failure mechanismunder high temperature and impact loading. In this paper, sandstone in coal measuresis the main study object, and experiment researched measure and theory analyzed isthe method and means. With the help of advanced testing technology and analysismethods, combined with modern mechanical theory, we make systematic study onthis condition, and obtain some innovative achievements(1) By using split hopkinson pressure bar testing system (SHPB), we makemeasurement on uniaxial compression of sandstone in coal measures in differentstrain rate. Then we obtain its change rules on stress-strain curve, dynamic elasticitymodulus, peak stress and peak strain, and put forward the influence between strainrate to its damage and energy dissipation.(2)By using SHPB testing system, GWD-02A temperature loading and controlsystem, we make systematic research on its mechanical properties and thestrain-rate-effect of damage characteristics. Then we obtain these rules under hightemperature to high strain rate, and put forward the influence between the sampledestruction and energy dissipation to temperature and its loading rate.(3)Based on the sample material composition and fracture morphologycharacteristics, we make experiment with x-ray diffraction and scanning electronmicroscope. Then we obtain its composition and grain size changing with temperatureand its loading rate, and analyze the sample’s damage mode changing with strain rateand temperature, which reveals the microcosmic fracture mechanism at a certainextent.(4)According to rock fracture theory, we build its fracture evolution andconstitutive equation by considering temperature and strain rate effect, and confirmthe detailed parameter by the experimental curve. Compared with it, there is very good corroborating between the constitutive equations to experiment data.The result should be the main reference to the structure damage of sandstone incoal measures and stability analysis for engineering.