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水泥土复合管桩(简称PPC桩)作为一种新桩型,尚没有现成的理论可供利用。为了研究PPC桩的水平承载机理,采用现场试验,实测得到了水平荷载下PPC桩的承载能力、破坏模式及水平位移。通过与其他桩型水平承载力特征值取值方法的对比,得到了适用于PPC桩的水平承载力特征值取值标准。研究表明:加载模式对PPC桩的受力特点、破坏模式有影响,整体加载时,临界荷载与极限荷载的比值大于芯桩加载时的值。整体加载时属塑性破坏,芯桩加载时属脆性破坏。单桩水平位移影响范围为2.5倍桩径,整体加载时单桩水平承载力特征值取临界荷载的0.75倍,芯桩加载时取临界荷载的0.6倍,按此标准取值的单桩水平承载力特征值安全系数不低于2。试验结果可以为水平受荷PPC桩的检测与设计提供参考。
Cement-soil composite pipe pile (referred to as PPC pile) as a new type of pile, there is no ready-made theory available. In order to study the horizontal bearing mechanism of PPC piles, the bearing capacity, failure mode and horizontal displacement of PPC piles under horizontal load were measured by field test. By comparing with the other methods of calculating the horizontal bearing capacity eigenvalue of pile type, the criterion of horizontal bearing capacity eigenvalue suitable for PPC pile is obtained. The results show that the loading mode has an impact on the stress characteristics and failure modes of PPC piles, and the ratio of critical loads to ultimate loads is larger than that of core piles under loading. When the overall load is a plastic damage, brittle damage when loading the core pile. The influence range of single pile horizontal displacement is 2.5 times of pile diameter. When the whole load is loaded, the characteristic value of single pile horizontal bearing capacity is 0.75 times of the critical load. When the core pile is loaded, 0.6 times of the critical load is taken. According to this standard, Force characteristic value safety factor of not less than two. The test results can provide a reference for the detection and design of horizontally loaded PPC piles.