建基岩体开挖前后的声波曲线特性及其成因分析

自然斜坡在形成演化过程中,受区域构造、河谷下切、地壳隆升以及外部营力(如风化卸荷)作用,加之岩体物理力学特性等多种地质环境因素影响,可在岸坡浅表层(由表及里)形成应力释放区、应力调整区和原始地应力稳定区;但在岸坡(建基)岩体人工开挖过程中,由于爆破扰动及岩体瞬间卸荷等影响,以上应力分区将重新波动调整。声波VP作为评价岩体质量优劣的一个重要指标,因具备简便、快速、准确、可靠等特点得到了广泛应用与发展。现就此以前期勘探平硐声波测试及开挖坝面岩体质量单孔声波检测结果为基础,讨论建基岩体开挖前后波速曲线的形态特征以及应力分区分布范围,并分析导致曲线形态的地质原因,以期为坝基开挖及后续声波监测工作等提供一定的科学依据。

Analysis of Sound Wave Curve Characteristics and Causes of Dam Base Surface Rock Mass before and after Excavation

Under the impacts of regional structure,river valley undercutting,crust uplifting,stress release process and the rock physics mechanics features,three different zones can be identified in the shallow layer of natural slopes in the process of formation and evolution,including stress relaxation zone,stress re-adjustment zone and stress stability zone.Artificial excavation and vibration effect would bring about the adjustment of the distribution range of the stress.Sound wave,as a major index for evaluating th...