微型钢管桩桩间土滑塌机理与监测验证

桩间土滑塌是基坑工程中经常出现的一种破坏形式,对基坑工程的安全产生重大威胁,因此,研究桩间土滑塌的条件和机理就显得尤为重要。本文结合某微型钢管桩基坑支护工程桩间土滑塌实例,对桩间土滑塌的机理进行了详细的研究和阐述,并结合全自动远程实时监测装置测得的地表沉降数据辅助验证。研究结果表明:桩间土的滑塌可分为桩间土拱形成、蠕变与塑性变形、桩间土拱破坏三个阶段,滑塌的触发原因为地下水位回升,导致土体抗剪强度降低,土拱破坏;采用自主研发的全自动远程实时监测系统能够及时准确的测量出地表沉降,并反应出基坑开挖、气温变化及降排水条件等对坑周土体地表沉降的影响,对保障基坑安全施工有重要的意义。

Sliding Mechanism and Monitoring Verification of the Soil between Micro Steel Tube Piles

Soil sliding between piles is a form of damage often encountered in the excavation engineering, producing major threat to the safety of the foundation pit, therefore, to study the mechanism of the soil sliding between piles is particularly important. Based on a micro steel tube pile foundation pit supporting, this article studies and expounds the mechanism of soil sliding between piles in detail with combining the ground surface subsidence data of the automatic remote real-time monitoring device to verify the mechanism. Research results show that the soil sliding between piles can be divided into three stages including soil arch forming stage, creep and plastic deformation stage and soil arch damaging stage. The trigger of the sliding is the underground water level recovery, resulting in decrease of shear strength of the soil and the soil arch damage; by using independently developed fully automatic remote real-time monitoring system the surface subsidence can be accurately and timely measured, to reflect the influence of the foundation pit excavation, the temperature change and drainage conditions on the surface subsidence, which has important significance to foundation pit safety.