单轴循环载荷与渗透水压下预应力裂隙岩石破坏试验研究

Failure characteristics of prestress fractured rock under uniaxial cyclic loading and seepage water pressure

为研究受地应力与渗透水压耦合作用下的深部岩体受到爆破等动力扰动的力学响应,研制了渗透水压加载装置,对含裂纹类岩石材料的混凝土试样加载预应力后,进行有渗透水压作用和无渗透水压作用下单轴循环加卸载压缩破坏对比试验。试验结果表明,在试样弹性阶段加载有限次循环载荷有助于类岩石材料的强化;在有渗透水压作用下,单轴循环加卸载后岩石的强度降低,降低的程度与循环载荷加载时预应力的大小有关,在弹性阶段加载循环载荷的岩石强度高于在损伤阶段加载循环载荷的岩石强度,而且在渗透水压作用下岩石的应变大于无渗透水压作用下岩石的应变。具有岩爆倾向性的岩石可以通过加载、卸载产生损伤以降低其岩爆倾向性,同时低渗透水压的作用可使岩爆降低程度更剧。

In this paper, to reveal the mechanical response of deep rock under the coupled action of ground stress and seepage water pressure when facing dynamic disturbance such as blasting, the seepage pressure loading device was developed, and the uniaxial cyclic loading tests of prestress fractured concrete samples, coupling with and without seepage water pressure, were carried out respectively. The results show that the limited uniaxial cyclic loading is helpful to the strengthening of concrete material when it is in the elastic stage. Under the action of seepage water pressure, the rock strength is reduced after the uniaxial cyclic loading, while the reduction degree is related to the prestress of cyclic loading. Meanwhile, when the cyclic loading is compressed in the elastic stage, the rock strength is higher than that when cyclic loading is compressed in the damage stage. In addition, the rock strain under the action of seepage water pressure is greater than that without seepage water pressure. Therefore, the burst proneness of rock mass can be reduced by the action of cyclic loading and unloading, and the low seepage water pressure can further decrease the rock burst proneness.