含交叉节理黄砂岩不同冲击载荷作用下破坏机理的研究

Study on Failure Mechanism of Yellow Sandstone with cross Joints under Different Impact Loads

为了研究力–热耦合作用下含交叉节理岩石的动力学性质,本文利用SHPB实验装置和配套高温环境箱,对不同温度环境下如25℃、100℃、300℃、500℃和700℃、不同冲击载荷作用下含交叉节理黄砂岩试样进行了五种冲击荷载的试验研究。研究表明:(1) 动态峰值应力与冲击载荷呈二次多项式函数关系,正相关性显著。100℃~500℃范围内温度对动态峰值应力影响显著,500℃~700℃范围内温度对动态峰值应力影响较小,其中300℃温度动态峰值应力最大。(2) 试样破坏形态不同,随着温度的增加由脆性破坏逐渐向延脆性破坏转化;随冲击载荷的增加,破裂面逐渐变多,破碎程度逐渐加剧,碎块尺寸变小;整体上25℃~300℃破碎程度比300℃~700℃破碎程度高。

In order to study the dynamic properties of rocks under the action of force-thermal coupling, the SHPB experiment device and the supporting high-temperature environment box were used to carry out five kinds of experimental studies on the yellow sandstone samples containing cross joints under impact loads of 25˚C, 100˚C, 300˚C, 500˚C and 700˚C under different temperature en-vironments. The results show that: (1) The dynamic peak stress has a quadratic polynomial func-tion relation with the impact load, and the positive correlation is significant. Temperature has sig-nificant influence on dynamic peak stress in the range of 100˚C^500˚C, while temperature has little influence on dynamic peak stress in the range of 500˚C^700˚C. The maximum dynamic peak stress was found at 300˚C. (2) The failure modes of the samples are different. With the increase of temperature, the brittle failure gradually transforms to the brittle failure. With the increase of the impact load, the fracture surface becomes more and more, the crushing degree becomes more and more serious, and the size of the pieces becomes smaller. On the whole, the crushing degree of 25˚C^300˚C is higher than that of 300˚C^700˚C.