不同含水状态花岗岩断裂力学行为及声发射特征

利用MTS815 Flex Test GT岩石力学试验系统及声发射(AE)三维定位实时监测系统,对两种不同含水状态的深部细粒英云闪长岩进行了三点弯曲试验,得到烘干状态及饱水状态下花岗岩的载荷–LPD曲线、声发射振铃计数率、AE撞击数曲线。试验结果表明,在水的影响下花岗岩的断裂力学特性和声发射特征都有较大变化。饱水状态岩样的平均断裂韧度为干燥状态下的87.5%,且在试验过程中整体的变形变大,其刚度变小,脆性减弱,强度变低。在岩样三点弯曲的各个阶段,饱水岩样的声发射振铃计数率远小于干燥状态岩样;在试验过程中出现了明显的Kaiser效应。岩样以V型截面拉断破坏为主;饱和岩样声发射事件数远大于干燥岩样。研究结果对于受含水层影响的深部花岗岩岩土工程设计及施工具有重要的理论及实际指导意义。

Mechanical behaviors and acoustic emission characteristics of fracture of granite under different moisture conditions

The three-point bending tests on Beishan granite under different moisture conditions are carried out by using the MTS815 Flex Test GT and acoustic emission (AE) three-dimensional positioning monitoring system to obtain the load-LPD curves, AE ringing count rates and curves of AE hitting number. The results show that there is significant influence of water on the fracture mechanics and AE features. The average fracture toughness of the water-saturated samples is 87.5% of the dry ones, and the stiffness and strength decrease apparently. The water-saturated granite shows greater deformation and weaker stiffness. At different stages of the tests, the AE ringing count rate of the water-saturated samples is far less than that of the dry ones, and the water-saturated samples show obvious Kaiser effect. The main failure of the samples is the tensile failure with v-shaped cross-section features. The AE events of the water-saturated samples are more than those of the dry ones. The results of this study are of important theoretical and practical significance for the design and construction of the deep granite geotechnical engineering influenced by aquifers.