Study On Rock Crack Propagation Induced By Temperature Stress

Under the effect of temperature shock,the temperature stress inside the rock mass can easily cause the deformation and fracture of the rock mass,which will threaten the engineering safety.Therefore,studying the effect of temperature on rock has guiding significance for engineering construction.This article uses RFPA numerical simulation engineering software as a tool,the theory of heat conduction as basis and actual engineering as background,to construct multiple sets of models that to simulate the temperature and stress distribution of rock subjected to temperature shocks,by which the process of rock failure is reproduced and the principle of temperature effect is analyzed.Besides,the impact of various factors on temperature-breaking rock are concerned.This article mainly did the following work:(1)A flat model was established.By performing cold shocks on the boundary,the plate temperature and the minimum principal stress distribution during cold shock were obtained.At the same time,the cracking process under cold shock was simulated,and the influence of heat transfer coefficient and thermal conductivity on the cold shock was considered.The results show that the increase of heat transfer coefficient is conducive to rock fracture,and the thermal conductivity coefficient has little effect on rock fracture.(2)That the rock mass engineering is in the ground stress environment is fully considered,so a circular hole model with ground stress is built.By changing different side pressure coefficients,cold shock simulation under different ground stress conditions can be realized.When the side pressure coefficient is less than 1,the crack tends to initiate and expand at the upper and lower parts of the circular hole;when the side pressure coefficient is equal to 1,the crack development site has no directionality;when the side pressure coefficient is greater than 1,the crack tends to sprout around the round hole.(3)This paper conducted a comparative analysis on the current two kinds of temperature impact(thermal shock and cold shock).By changing the temperature at inner diameter of the disk,the crack propagation process under two temperature impact modes is simulated.Studies have shown that: the cold shock is more likely to produce cracks,which propagate from the inside to the outside;the temperature difference required to generate cracks due to thermal shock is larger,and cracks often occur at the outer diameter.