强降雨条件下框架预应力锚杆柔性支护结构整体稳定性影响参数分析

为完善框架预应力锚杆柔性支护结构稳定性研究,针对该结构的稳定性分析和设计均未考虑降雨入渗影响的现状,基于GeoStudio软件,分析了黄土地区强降雨条件下的框架预应力锚杆柔性支护结构的整体稳定性影响参数,在分析中考虑了土体含水率变化对摩擦型灌浆锚杆极限抗拔承载力的影响。分析结果表明:降雨持时、降雨强度和地下水位对框架预应力锚杆柔性支护结构的整体稳定性有明显的影响; 土体饱和渗透系数的影响十分显著; 渗透各向异性的影响可以忽略; 降雨条件下框架预应力锚杆柔性支护结构的安全系数变化存在滞后效应:随着降雨持时和土体饱和渗透系数增大,滞后效应逐渐减弱; 降雨强度越大、初始地下水位越高,滞后效应越明显。本文的研究成果能为非饱和黄土地区框架预应力锚杆柔性支护结构考虑降雨影响的设计和施工提供指导。

PARAMETRIC ANALYSIS OF INFLUENCE ON GLOBAL STABILITY OF GRILLAGE FLEXIBLE SUPPORTING STRUCTURE WITH PRESTRESSED ANCHORS UNDER HEAVY RAINFALL

This paper aims to perfect the overall stability of grillage flexible supporting structure with prestressed anchors. According to the actuality, the stability analysis and design of the structure have not considered rainfall infiltration effect. Using the GeoStudio software, the overall stability parameters is analyzed for the grillage flexible supporting structure with prestressed anchors under the heavy rainfall conditions in loess area. It considers the soil moisture content influence of the ultimate uplift capacity of friction type grouting anchor. The result shows the following aspects. The rainfall duration, rainfall intensity and underground water level have obvious influence on the frame prestressed anchor flexible retaining structure. The influence of permeability anisotropy can be ignored. The safety factor of frame prestressed anchor flexible retaining structure under the condition of rainfall has lag effect. The greater the rainfall duration and saturated permeability coefficient are, the weaker the lag effect is. The greater the rainfall intensity and the higher the initial groundwater level are, the greater the lag effect is. The results of this study can be used as the guidance of the design and construction of grillage flexible supporting structure with prestressed anchors considering the influence of rainfall in unsaturated loess area.