渗透作用下土体蠕变与锚索锚固力损失特性研究

Study of anchorage force loss of anchor cable under seepage flow and soil creep

预应力锚索广泛应用于边坡、基坑等工程中,锚固力损失是影响其锚固效应的重要方面,由于锚固力失效而导致的工程事故屡见不鲜。特别是在降雨或者地下水丰富的地区,由于渗流作用等的影响更容易引起预应力锚索锚固体等应力状态的改变,导致锚索失效引发工程事故。以滨海某基坑为研究背景,以现场监测数据为基础,建立了一种综合考虑渗透作用下土体蠕变和预应力锚索锚固力损失三维本构模型,推导出土体蠕变和预应力锚索锚固力松弛方程。基于FLAC3D软件开发了相应的计算程序,分析了滨海某基坑渗透作用下土体蠕变和预应力锚索锚固力损失特性。结果显示,数值模拟结果与现场监测数据有较好的一致性,表明所建立的模型是正确和可行的。该方法可用于分析渗透作用下的预应力锚索锚固力损失特性,为类似工程提供理论指导和分析手段。

Pre-stressed anchor cables are widely used in tunnels, slopes and foundation pits. The loss of anchorage force affects the anchoring of pre-stressed anchor cable. The engineering accidents of anchorage failure often occur owing to the loss of anchorage force of pre-stressed anchor cable. The stress state of pre-stressed cable anchor is easily changed and anchor failure leads to engineering accident in water-affluent region. Based on the deformation data, this paper establishes a coupling constitutive model considering soil creep, anchorage force loss of pre-stressed anchor cable and seepage force. Then, the three-dimensional creep equation of soil and relaxation equation of anchoring force loss of pre-stressed anchor cables are deduced. Based on FLAC30 software, the corresponding procedure is developed to calculate and analyze the soil creep and anchoring force characteristics loss of the above mentioned foundation pit in coastal region. Combined with monitoring data, the above constitutive model is feasible and correct for analyzing anchoring force loss characteristics of pre-stressed anchor cables under seepage condition. The research results provide meaningful theoretical and oractical guide for other similar oroiects.