Experimental Study On Mechanical Properties Of Grit Stone After High Temperature

Temperature is an important factor affecting rock mechanical properties. When the rock is affected by temperature stress which results in damage, its strength and deformation were changed obviously. Temperature has a marked influence on rock mechanical properties. For the same rock, its mechanical properties express different characteristics after the actions of different temperature. However, when the temperature is fixed, to different rocks, its rock mechanical properties also are different.Two different grit-stones were investigated subjects in this thesis, the mechanical properties of grit-stone are preliminary studied after the action of high temperature, on basis of the normal triaxial-compression test and uniaxial compression test and Brazilian split test of grit-stone. Then the conclussions are summarized as following:(1)The change of grit-stone's density is very small after the action of temperature, in many conditions it almost can be neglected. The longitudinal wave velocity of grit-stone's elastic appears reducing tendency after the action of high temperature. The relationship between longitudinal wave and temperature is linear. With the increasing of the heating temperature, the longitudinal wave velocity of grit-stone linearly monotone decrease. The longitudinal wave slip of grit-stone's elastic appears increasing tendency after the action of high temperature. The relationship between longitudinal wave and temperature is linear. With the increasing of heating temperature, the longitudinal wave velocity of grit-stone quadric unlinearly monotone increase.(2) The uniaxial tensile strength,elastic modulus and uniaxial compress strength of grit-stone firstly increase before R℃(uniaxial tensile strength between 400℃to 500℃,elastic modulus and uniaxial compress strength between300℃to 400℃) then decrease after R℃in general tendency, with the increasing of heating temperature, after the action of high temperature,and the deformation and peak strain are separate monotone decreasing and monotone increasing in general tendency.(3)In the condition of triaxial compression, with the increasing of confining compress, the cohesion force, the internal friction and elastic modulus of grit-stone,firstly increase before 300℃, and then decrease after 300℃,while the heating temperature is a constant. And the axial peak strain monotonely increasees all the time. When the confining compress is fixed, with the increasing of heating temperature, the triaxial compression strength and elastic modulus of grit-stone,firstly increase before300℃, and then decrease after 300℃,and the axial peak strain firstly monotonely increasees.