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).