不同恒温时间加热下花岗岩冲击压缩力学特性及破碎特征OA北大核心CSTPCD

In order to study the effect of real-time high temperature action at different constant temperature time on the mechanical properties and failure characteristics of granite shock compression,the SHPB impact compression test at high temperature and screening test were carried out.Firstly,the granite was heated to 700℃and subjected to five different time length constant temperature heat treatment of 0,30,60,90 and 120 min.Secondly,SHPB test at high temperature was carried out by synchronous rod device without cooling the sample.The crushed specimens were collected for screening test.Finally,combined with the data of compressive strength and fractal dimension,the mechanical properties and crushing characteristics of granite were analyzed.The results show that the constant temperature time has a great influence on the dynamic compressive strength of granite,and the compressive strength of the specimen decreases significantly with the increase of the constant temperature time.The degree of granite fragmentation increases with the increase of constant temperature time,which shows that the number of fine blocks in broken specimens gradually decreases and the number of fine particles increases.The fractal dimension of granite impact compression failure at different constant temperature duration is concentrated in the range of 2.2-2.7,and presents a positive correlation with the constant temperature duration.The dynamic compressive capacity and macro fracture fractal characteristics of granite at real-time high temperature have obvious strain rate strengthening effect.