台州站薄壁筒桩加固软基的受力情况研究

Research on the Stressing Situation of Thin-Wall Cylindrical Pile for Reinforcing Soft Foundation of Taizhou Railway Station

研究目的:现浇薄壁筒桩作为一种软土地基处理的新技术,在甬台温客运专线台州车站施工中,首次应用于铁路软土地基处理。笔者在车站筒桩加固路段选择两个监测断面,分别为有盖板和无盖板区段,进行原位试验。根据土压力计、孔压计的监测数据对两区段进行加固情况的受力分析,揭示薄壁筒桩加固铁路软基的受力规律。研究结论:薄壁筒桩复合地基荷载主要以筒桩承担,筒桩受力以侧向摩擦阻力为主。筒桩加盖板后,能更好发挥桩的承载力作用;筒桩周围土的受力与有效面积相关,其应力比随着荷载的增大而增大;薄壁筒桩能有效地防止软土地基的侧向挤土变形,筒桩复合地基抗水平能力大、抗侧滑移能力强,使高路堤路段具有良好的抗滑性;薄壁筒桩成桩质量稳定、单桩承载力高、复合地基具有良好的群桩基础承载力性能;筒桩复合地基,变形小,特别是工后沉降小,加固的软基强度和刚度大大增强。

Research purposes： Cast - in - situ concrete thin - wall cylindrical pile is a new technique for reinforcing soft foundation and it was used for the soft foundation of the Taizhou Railway Station, which was the first time to use it for reinforcing the soft foundation of railway in China. The two monitoring sections were chosen to do in - situ tests, namely one section with cover plate and another with no cover plate. The stressing situation in reinforcing the soft foundation of the two section is analyzed according to the monitored data obtained from soil pressure meter and hole pressure meter and the stressing law in reinforcing the soft foundation with thin -wall cylindrical pile is discovered. Research conclusions：The cylindrical pile bears the most load of the composite and its stressing is mainly from side frictional force. After the cover plate is added to the cylindrical pile, the cylindrical pile can give full play to beating load. The stressing of soil around cylindrical pile is related to the effective area, and its stress ratio increases with the increase of the load. Application of thin wall cylindrical pile can prevent the soft foundation from lateral distortion by compacting earth. subgrade is good and the anti - side slipping capacity As the anti - horizontal capacity of cylindrical pile＇s composite is perfect, the embankment area of high road is good at anti - sliding. The piling quality of the thin - wall cylindrical pile is stable, the single pile＇s bearing composite foundation has a good bearing capacity of complex piles foundation. The distortion capacity is good, and the of cylindrical pile is less,especially the post - construction subsidence is small. The strength and rigidity of the reinforced soft foundation are much improved.