成桩方式对微型桩承载力影响的室内试验研究

Laboratory Study on Load-Bearing Capacity of Micropiles by Using Different Construction Methods

微型桩可采用投石注浆法或者直接灌注细石混凝土法成桩。结合室内试验,对不同成桩方式对微型桩承载力的影响进行了研究。研究表明:压力注浆能够提高微型桩的竖向承载力,在进行微型桩竖向承载力计算时应考虑二次注浆的提升效果;为保证微型桩成桩质量,应用于输电线路工程的微型桩应进行二次注浆;压力注浆对微型桩水平承载力的影响因上部土层性质而易,在进行微型桩水平承载力计算时不考虑压力注浆的影响。

Micropiles can be constructed by pressure grouting method or concreting method.In this paper,laboratory tests about load-bearing capacity of micropiles by using different construction methods were done.Study shows that the pressure grouting can increase vertical load-bearing capacity of micropiles,when calculating the vertical capacity of two-grouting micropiles the effect of the second grouting should be considered;micropiles used in transmission line should be made by two-grouting technology to ensure the quality of micropiles;the influence of pressure grouting on horizontal load-bearing capacity of micropiles is up to the nature of the upper soil layer,calculating the horizontal capacity of micropiles doesn＇t consider the effect of pressure grouting.