The Influence Of Temperature Change On The Mechanical Properties Of Lining Concrete Is Studied

In view of the present large buried depth high geothermal tunnel operation period when water temperature drop on the mechanical behavior of lining concrete,concrete test blocks with different temperature maintenace are cooled in different cooling modes.To study the influence of temperature change on the mechanical properties of concrete.Firstly,the single axial compression and split tensile test of concrete test block and the determination of dynamic elastic modulus are carried out to obtain the corresponding mechanical data,and obtain the effects of high temperature and different cooling methods on the mechanical properties of concrete were obtained;With the help of infrared thermal imageing technology,the surface temperature field-infrared thermal image of the concrete test block was obtained under uniaxial compression,to relate between the surface temperature variation and the distribution of cracks in concrete,the distribution of cracks in the surface of the concrete test blocks in each stress state corresponds to the temperature distribution in the infrared thermal image map,the change of infrared radiation temperature in the test block surface was analyzed by means of average infrared radiation temperature(AIRT)and entropy theory;fractal theory is used to obtain the fractal dimension of surface crack of concrete test block,the variation of fractal dimension of concrete surface cracks with different temperature and cooling mode was analyzed.Provide reference and data support for the high geothermal tunnel project and its related research.The test results show that the temperature drop has a certain effect on the strength of concrete.In particular,the impact of cracking and tensile strength of concrete is greatest,and the greater the temperature difference,the more serious the damage;The fractal dimension of surface crack of concrete test block was analyzed:It is concluded that the surface crack of concrete test block with cold water cooling is faster than that of natural cooling,and the development of the surface crack of the natural cooling concrete test block needs a smooth transition zone;The destruction of the concrete block will be accompanied by the release of energy,the mean infrared radiation temperature can not effectively express the difference of temperature field distribution,the entropy can indirectly the damage of concrete.