卸荷挡墙工作机理及设计分析方法研究

Research on the Working Mechanism and Design Method of Unloading Retaining Wall

为系统研究卸荷挡墙卸荷机理及工程设计方法,确定影响卸荷挡墙结构承载和稳定性的关键影响因素,采用结构力学分析和土压力理论,建立卸荷挡墙结构承载分析模型,开展卸荷板荷载传递系数m、卸荷板位置及长度等因素对卸荷挡墙结构承载和稳定性的影响规律研究,提出结构设计关键性控制指标的确定方法,从结构承载和挡墙稳定性两个方面揭示卸荷挡墙工作机理。结果表明:卸荷挡墙通过卸荷板竖向承载和荷载遮蔽效应优化调整了墙后土压力传递路径,减小卸荷板下部侧向土压力,降低墙面板和底板结构内力幅值,墙体抗倾覆稳定性平均提高约8%,抗滑移稳定性平均提高约20%;建立的卸荷挡墙结构承载模型适用于结构内力与承载性能分析,能够有效反映卸荷板对卸荷挡墙结构承载的影响规律;卸荷挡墙承载能力随卸荷板荷载传递系数m的增加而增大,m=0.4时分析结果最为合理有效;卸荷板位置宜为0.5~0.7倍墙面板高度,卸荷板长度宜为0.5~0.7倍踵板长度,对卸荷挡墙结构承载最为有利。

In order to systematically study the unloading mechanism,the design method,the key factors affecting bearing and stability of unloading retaining wall,both structural mechanics analysis and earth pressure theory were applied in the research.And then,a load-bearing analysis model was established and applied in the influences research of unloading plate transfer coefficient m,the position and the length.Moreover,the key control indexes determination method was also proposed out accordingly,which deeply revealed the unloading retaining wall working mechanism through the structural load-bearing and stability.With the research results,regarding to the unloading retaining wall,earth pressure transmission path would be changed by the unloading plate vertical bearing and load shielding effect,and the lateral earth pressure under the unloading plate as well as the internal force amplitude were also reduced greatly,anti-overturning stability was increased by about 8%on average,and the anti-sliding stability was increased by about 20%on average.The unloading retaining wall load-bearing model was reasonable,and effectively reflected the influence of the unloading plate.The bearing capacity of the unloading retaining wall was increasing with the unloading plate transfer coefficient m,and the analysis result was more reasonable and effective as m=0.4.Position of the unloading board with 0.5~0.7 times wall panel height and the length with 0.5~0.7 times heel plate length were more effective for the unloading retaining wall working.