Trapdoor位移相关土压力及抗沉陷加筋设计新方法

传统考虑土拱效应的Trapdoor松动土压力与位移无关,已逐渐不能满足工程设计需要。通过综合分析Trapdoor表面土压力随位移变化的规律,提出了Trapdoor与位移相关土压力的表达式。对于不同的土性参数和Trapdoor尺寸,计算土压力与模型试验及FLAC数值分析结果吻合良好。利用所提出的Trapdoor位移相关土压力,建立了抗局部沉陷加筋设计新方法,克服了传统Giroud(1990)设计方法不能考虑沉陷区上方土压力随沉陷位移变化的不足,从而更符合实际情况。通过扩建填埋场封顶系统及中间衬垫系统的抗局部沉陷分析及设计发现,对于封顶系统传统Giroud(1990)设计方法偏保守;而对于中间衬垫系统,上覆堆体厚度明显影响加筋体的允许张拉强度,当上覆堆体厚度H较大时(沟渠型沉陷:H>32 m,圆形沉陷:H>50 m),传统Giroud(1990)设计方法偏不安全。

Trapdoor deflection-related earth pressure and new design method of reinforcements to resist local subsidence

【Abstract】 The traditional Trapdoor loose earth pressure taking into account the soil-arching effect is independent of the Trapdoor deflection,which can not fully satisfy the requirements of the present engineering design.The expression of deflection-related Trapdoor normal earth pressure is presented by analyzing the relationship between earth pressure normally acting on the surface of Trapdoor and the Trapdoor deflection.For various parameters of overlying soil and the width of Trapdoor,Trapdoor normal earth pressures calculated by the proposed expression are in good agreement with those of the available model tests and FLAC numerical analyses.A new design method of reinforcements to resist the local subsidence is established using the proposed deflection-related Trapdoor earth pressure.In comparison with the traditional Giroud(1990) design method which can not consider the relationship between the normal earth pressure and the vertical deflection of reinforcements,the present design method is in more accordance with the actual engineering situation.Analysis and design to resist local subsidence for covering system and intermediate liner of an expanded landfill are carried out,showing that the thickness of the overlying soil can heavily influence the allowable tensile strength of reinforcements,and that the traditional Giroud(1990) design method is not recommended if the thickness of the overlying soil H is large enough(trench subsidence: H>32 m,circular subsidence: H>50 m).