深部损伤岩体弹性模量的确定方法

The determination method of elastic modulus of deep damage rock mass

深部地下洞室开挖后,洞室表层围岩会出现大量微裂隙,在二次应力场调整过程中,这些微裂隙逐步扩展贯通导致围岩出现片帮、板裂以及塌落等损伤现象,从而无法利用钻孔取样对表层损伤区岩体的弹性模量进行确定。本文基于损伤力学原理,利用现场声波测试与经验公式对损伤岩体的弹性模量进行初步判断,确定其大致范围,然后联合神经网络与损伤本构模型RDM对岩体的弹性模量进行精确反演,进而获得损伤岩体弹性模量的分布规律。通过红透山27采场的实际应用,证明了该方法确定深部损伤岩体弹性模量以及岩体完整性分布规律的可行性。

Excavation in deep underground cavity results in numerous micro-cracks on the surface of surrounding rock. In the readjusting process of stress field, propagation and coalescence of these cracks will cause severe problems such as spalling, board split and collapse, which make it difficult to deter-mine the elastic modulus in the damaged zones using drilling method. In this paper, based on the dam-age mechanics principle, the general range of the elastic modulus in the damaged zones is preliminary judged by in-situ sonic test combined with empirical formula, and then the distributing regularity of elastic modulus in damaged zones is obtained by accurate inversion using neutral network and RDM model. This approach is applied in the 27th stope of Hongtoushan Mine and it has been proved to be va-lid and feasible to determine both the elastic modulus of damaged rock mass and distribution regularity of rock mass integrity in deep underground projects.