管桩加固软土路基桩土应力现场试验

Field Experiment of Pile-Soil Stress of Soft Subgrade Reinforced by Pre-stressed Concrete Piles

利用现场试验的方法,在地质情况相近的软基管桩路段采取了4种不同的褥垫层设置方式,并在4个监测断面埋设了大量的土压力盒对桩土应力进行严密监控,获得大量数据。通过对监测数据的获取与整理,对土压应力以及桩土应力比的时效性等特性进行了分析,试验数据反映了以桩土应力比峰值点为分界点,桩土应力协调分两阶段,由土体瞬时沉降引起的应力协调是桩土协调工作的第一阶段,由主固结引起的为第二阶段;同时通过对比分析,对褥垫层设置提出了合理的建议。

In the field experiment, different cushions were placed in four sections of the prestressed concrete pile composition foundation under the same geologic condition. A lot of earth pressure cells were embedded in the soil on the plane of piles top to detect the stress rigorously. The data was achieved and analyzed. The time effect characters of earth pressure and pile-soil ratio were discovered. The data reflects the stress coordination of the piles and soil which can be divided into two processes. The first process is coursed by immediate settlement and before pile- soil ratio reaches the peak value. The process after the pile-soil ratio reaches the peak value is the second process, which is coursed by primary settlement. Reasonable suggestions of the design of cushion were also put forward.