延安地区某边坡双排抗滑桩支护分析

Analysis on double-row anti-slide piles of slope in Yanan

以延安黄土梁峁地区城市开发过程中出现的某建筑高边坡双排桩支护结构为研究对象,通过有限元程序Marc,建立数值计算模型,研究双排桩的受力机理。主要分析了桩土接触、桩体刚度、联系梁刚度、前后排桩体长度以及桩距对双排抗滑桩受力的影响。研究结果表明:随土体强度减小,后桩与土体的接触部分向桩顶发展,而前桩的接触部分则从桩顶向下减少;前桩上半部分拉应力较大,尤其在边坡根部,应力达到最大,而后桩的最大应力出现在桩顶部以下14～15m处;前、后排桩最大拉应力之比约为3/2,在承载力计算时,弯矩按3/2的比例进行分配;桩顶联梁的高度取桩身直径的60%～70%,前后桩净距取桩径的1.5倍～2.0倍较为合理。

During the urbanization process of Yanan,there are high building slopes retained with double-row anti-slide piles in loess hilly regions.The mechanism of the double-row anti-slide piles were analyzed with the help of Marc program.The influencing factors were analyzed,which included the pile-soil interaction,the pile＇s rigidity,the crossbeam＇s rigidity,the length of the double-row piles and their distance.The results show that with the reduce of the soil＇s strength,the part of the front pile which has contact with the soil directly extends to the top of the pile,but the part of the back pile which has contact with the soil directly shrinks from the top of the pile.The tensile stresses of the upper half of the front pile are bigger.Especially on the root of the slope the tensile stresses reach the biggest.But the biggest tensile stresses of the back pile lie on the 14 m to 15 m from its top.The ratio of the biggest tensile stresses of the front pile and the back pile is about 3/2.When calculating the capability,the bending moment can be proportional distributed with 3/2.The height of the tie beam on the pile top is about 60% to 70% of the pile＇s diameter.The distance between the front pile with the back pile is about 1.5 to 2 times of the pile＇s diameter.14 figs,5 refs.