高速荷重下における岩石の力学的性質 (第1報)
1969 年 85 巻 979 号 p. 911-916
詳細
1969 年 85 巻 979 号 p. 911-916
It is the purpose of this study to find out the mechanicl behaviours of rocks under various loading-rates which ranged from 1.0×10-1kg/cm2/sec to 8.0×107kg/cm2/sec. The high rates of loading for the rock specimen have been obtained by the use of a high-speed compressive testing machine.
In the case of the high-speed loading test, which is undertaken for the purpose of comparing with the low-speed loading test, the shock waves should be eliminated, so as not to expose the rock specimen to impact loading.
From the above consideration, a new high-speed compressive testing machine, which is applied the load to the rock specimen by using the underwater explosive, has been designed.
The results of this investigation, using 10 kinds of rocks and a kind of cementmortar, have been summarized as follows.
The compressive strength of rocks increases with the loading-rate, for instance, “AKIYOSHI” marble at the rate of about 2.6 in respect of the ratio of the high-speed compressive strength to that of the low-speed. In this case, the average loading-rate of the high-speed test is about 2.5-2.6×107kg/cm2/sec, and the average loading-rate of the low-speed test is about 1.0×10-1kg/cm2/sec.
For the reason of this rate effect, it may be concluded that the effect of the pore, which exists in the rock, should be considered for, the occurrence of the rate effect.
