对于存在安全隐患且急需抢险处治的的滑坡、路堤边坡、基坑等救灾工程,坡体稳定性差,传统支挡结构难以实现快速施作,而微型桩具有明显优越性。但不同形式的微型桩,其承载力及破坏特征不同。通过改进yas-2000型压力试验机,并将其用于测试钢筋混凝土桩、钢管混凝土配钢筋桩及钢管混凝土配工字钢桩的抗弯承载力,结果表明:①钢筋混凝土桩的受力全过程可分为3个阶段,即未裂阶段、裂缝阶段及破坏阶段;②钢管混凝土配钢筋桩及钢管混凝土配工字钢桩的受力过程可分为4个阶段,即压实阶段、弹性阶段、弹塑性阶段和强化阶段;③通过对比分析上述3种不同结构微型桩的荷载-位移曲线得出在3种不同结构的微型桩中,直径相同时钢管混凝土配工字钢桩的抗弯承载力最大,其极限弯矩值为209.21 kN·m。

Micropile is superior to conventional retaining structures in the emergency treatment of landslide, embankment slope, or foundation pit with poor stability. Since the bearing capacity and failure characteristics of different micropiles vary, we improved the yas-2000 compression testing machine and applied it to measuring the flexural bearing capacity of three different micropiles: reinforced concrete pile, steel pipe concrete filled rebar pile, and steel pipe concrete filled I-beam pile. Results unveiled that the whole process of force acting on reinforced concrete pile can be divided according to three phases, namely, uncracked phase, cracked phase, and destruction phase. The stress process of steel pipe concrete filled rebar pile, and steel pipe concrete filled I-beam pile can be divided into four phases, compaction phase, elastic phase, elasto-plastic phase, and reinforcement phase. In addition, comparison of the load-displacement curves of these three micropiles revealed that given the same diameter, steel pipe concrete filled I-beam pile has the largest flexural bearing capacity with the ultimate bending moment reaching 209.21 kN·m.