史前土遗址模拟考古探方发掘期间的稳定性监测和评价（英文）

Stability monitoring and evaluation of the modeled test square for prehistoric earthen sites during excavation period

为了研究考古开挖过程中的探方稳定性,以杭州地区良渚遗址为例,开挖了长、宽为5 m,深度为2.3m,中间附带考古柱的模拟考古探方.在开挖过程中实时监测探方和邻近区域的稳定性参数,包括地面沉降、侧向位移、孔隙水压力和地下水位监测.监测数据表明,由于降水和探方侧边卸荷引起的地面沉降基本上随着离探方边缘距离的增大而减小,探方四边的侧向位移显示也沿深度方向的非线性变化且最大侧向位移值满足稳定性要求.孔隙压力和水位数据的变化表明,软土地区土体固结速率较慢,探方开挖之后的长期稳定性监测显得十分重要.同时,模拟探访发掘证明了台阶状开挖可以比垂直开挖更有效地减少侧向位移.模拟试验对于杭州良渚遗址的正式考古发掘提供了参考价值.

In order to explore the stability of test square during archaeological excavation for prehistoric earthen sites in Hangzhou, a modeled test square with 2. 3 min depth, inplane dimensions of 5 min width by 5 m in length, and an archaeological column in the middle was excavated by means of a top-down excavation technique. To investigate the stability performance of the modeled test square and the associated effect on the adjacent area, a real-time comprehensive instrumentation program was conducted during the excavation. Field observations included ground settlements, lateral displacement, pore pressure and underground water level. Monitoring data indicates that the ground settlement induced by dewatering and unloading action basically decreases with the increase of the distance away from the pit edge, and the lateral displacements at four sides showa nonlinear variation along the depth. The maximum value is far below the acceptable value regulated by the related standard,which validates the stability of the modeled test square during excavation. Variations of pore pressure and water level suggest that long-term stability should be paid more attention due to the slowconsolidation of soft soil. Meanwhile, it is proved that the step shape of the wall can resist lateral displacement more effectively than the vertical shape of wall. This case study provides insights into the real archaeological excavation in Hangzhou, in particular Liangzhu prehistoric earthen sites.