土钉–桩锚支护体系中土压力与m值对桩身水平位移的影响

Influence of Earth Pressure and m Value on Horizontal Displacement of Pile in Soil Nailing-pile Anchor Support System

土钉-桩锚支护结构的桩身位移变化一直是岩土工程界研究的热点,选取不同m值以及土压力的计算模式,位移计算结果都有较大的偏差。本文采用实测与计算值进行对比,辅以数值计算的方法,研究不同土压力与m值在不同工况下对桩身变形的影响。结果表明:土钉-桩锚支护体系中,采用朗肯土压力与实际土压力值有一定差距,可采用线性土压力值参考。采用工程地质规范的m值较采用经验公式求出的m值大,但解得的基坑变形相对较小,然而后者更贴近实际值。采用朗肯土压力下选用工程地质规范的m值求出的坑底位移与监测值和模拟值相近,其误差大小接近1mm,同时根据工程实际对桩顶位移的计算公式进行了修正。

The displacement of soil nail pile-anchor retaining structure has always been a hot topic in the soil engineering field.By using different m values and earth pressure calculation models,the results of displacement calculation are quite different.And comparison between measured and calculated values and numerical calculation was adopted.The results show that there was a certain difference between the Rankine earth pressure and the actual earth pressure in the soil nailing pile anchor support system,and it could use linear earth pressure for reference.The m value of the engineering geological codes was larger than that obtained by the empirical formula,but the deformation of the foundation pit was relatively small.The latter was closer to the actual value.The bottom displacement of foundation pit calculated by m value under the Rankine earth pressure was close to the monitoring value and the simulated value.According to the engineering practice,the error size was close to the 1 mm.The calculation formula of the pile top displacement was corrected.