微型桩-锚索系统加固边坡影响因素分析

Analysis of Influencing Factors on Stability of Micropile-cable System Reinforced Slope

研究目的:用微型桩加固边坡时,由于微型桩截面较小,所以难以进行大型边坡的加固。为了解决微型桩承载力低的问题,本文将微型桩与预应力锚索相结合,提出一种微型桩-锚索复合系统,结合工程实例研究微型桩-锚索系统加固边坡的效果,并对影响微型桩-锚索系统加固边坡稳定性的主要因素进行分析。研究结论:(1)微型桩-锚索系统可以明显提高加固边坡的稳定性,当锚索预应力约为400 kN时,复合系统的加固效果最好;(2)在微型桩-锚索系统中不同排微型桩受力具有不均匀性,作用在各排微型桩上的推力大小具有以下关系:反坡桩>竖直桩>顺坡桩;(3)当微型桩与竖向夹角为25°左右,预应力锚索与水平向夹角为14°左右时,微型桩-锚索复合系统加固边坡的效果最优;(4)实际工程中,建议将微型桩与预应力锚索之间接头部位进行焊接,并采用细石混凝土等进行封锚,可以保证二者协同受力;(5)本研究成果可为微型桩-锚索系统在山区边坡(滑坡)加固工程中的应用提供理论指导。

Research purposes： With smaller flexural rigidity, the lateral resistance of individual micropile is generally small. So it is impossible for micropiles to reinforcing the large scale slope failure. In order to improve the bearing capacity of micropiles, a new type of micropile - cable system was developed in this paper. The components and features of the system were introduced briefly. As such, a series of numerical slope stability analysis for a reinforced slope were performed using FLAC3D to investigate the behavior of the system and its influencing factors. Research conclusions： （ 1 ） It is found that the mieropile - cable system can largely improve the safety factor of the slope and the optimum prestressed force is almost 400 kN. （2） There is a big difference in the thrust among different rows of micropile of the system. During the failure of the reinforced slope, the rear row of micropile resist the maximum value of load, followed by the middle row of micropile, while the head row of mieropile resist the smallest value of load. （3） It is concluded from the limited parametric study that the reinforced slope is more stable when the head of pile is fixed and the inclined angle for micropile and cable in the system are respectively installed with 25° and 14°. （4） The link betweenthe head of micropile and cable should be welded each other and merged by fine concrete to make the system behave much compatibly. （5） The results provide a useful basis for applications of micropile - cable system in slope and landslide reinforcing in mountainous area.