FLAC^(3D)在潮湿环境史前考古土遗址直立探方稳定预判中的应用

Application of FLAC^(3D) in Pre-Judging the Stability of Vertical Excavation Units of Prehistoric Archaeological Sites in Moist Environments

潮湿环境中考古探方的失稳破坏不仅对遗址文物的保护不利,而且威胁着现场工作人员的人身安全。目前对潮湿环境下考古探方稳定性预判的研究较少。本文基于杭州潮湿地区的岩土参数采用FLAC3D数值模拟软件进行探方开挖前稳定性预判模拟计算。模拟探方为直立式,尺寸(长×宽×深)为5m×5m×2.4m。模拟发掘过程采取降排水措施。数值计算结果表明:(1)随开挖不断进行,坑壁水平位移逐渐增大,曲线形状呈"弓"型,水平位移由顶部至底部先增大到极值后减小,极值点位于距顶部1.75m的坑壁处。(2)最终安全系数为2.37。(3)得出了潜在滑移带所在位置,坑壁滑移带剪出口位于坑壁2.0m—2.4m处。计算结果可以为现场考古模拟发掘试验提供参考,为直立式考古探方稳定性预加固提供依据。

The instability of an archaeology excavation unit in moist environments is not only bad for the sites and protection of relics, but also threatens the personal safety of archaeologists. Little research on the stability of this equipment when used in such environments has been conducted at present, however. This study presents research on how to prejudge the stability of excavation units prior to excavation by applying the numerical simulation software FLAC^3D to the geological conditions and moist environment of Hangzhou when using a vertical excavation unit that measures 5m×5m×2.4m. The numerical calculation, combined with drainage measures also recorded during the simulation, yielded several results. First, during excavation the deformation of the pit wall increases gradually in the shape of a bow being drawn, and the horizontal displacement first increases to ex- tremum and then decreases from the top to the bottom. The point where the extremum is reached is 1.75 m from the top of the pit wall. Second, the stability coefficient is 2.37, and; finally, the location of the potential slip band is clearly observable, the opening of the slip band being 2.0m-2.4m from the top of the pit wall. These calculation results can provide reference for field archaeological excavation and evidence for preparatory reinforcement of vertical excavation units.