跨渠建筑物桩基与渠坡非协调变形的处理措施研究

Study on treatment of incompatible deformation between pile and side slopes of channel-crossing structures

南水北调中线工程沿线布置的交通桥和生产桥,其基础结构设置于两侧渠坡上,施工、运行期间的荷载(特别是水平荷载)作用于渠坡上的桩基础,在桩周一定的范围内将产生桩基与渠坡非协调变形,使基础与渠坡结构层的结合部产生裂缝,影响渠道的安全运行。本文通过理论分析、物理模型试验,研究了几种工程措施,以适应减少桩基与渠坡之间的非协调变形。结果表明:素混凝土措施对桩头变形有较大的抑制作用,同一水平荷载作用下桩头的水平位移明显减少;该措施还可以显著地降低桩身弯矩,减少配筋使用量。橡胶土措施及高塑性粘土措施适应非协调变形的能力相对较强,但是,在采用高塑性粘土措施时,需要校核桩体的抗弯能力。

All the foundation structures of the traffic and construction bridges arranged along the Mid-rout of the South-to-North Water Transfer Project are built on both the side slopes of the channel; from which the loads （especially horizontal load） act on the pile foundations of the channel slopes during the construction and operation, and then the incompatible deformation between both the pile and the slope will occur around the piles within a certain area, which will cause the cracking of the joint between the foundation and the slope structure layer, and finally influence the safe operation of the channel. Based on the relevant theoretical analysis and physical model test, several engineering measures are studied herein for decreasing the incompatible deformation concerned. The re- sults show that the measure of construction with plain concrete has a large inbibitional effect on the deformation from the pile head with significant decrease of the horizontal displacement under the effect from the simultaneous horizontal load. With the measure, the bending moment of the pile can be greatly reduced along with the decrease of the reinforcement. However, though measures of construction with the rubberized cement-soil or high plastic clay have stronger adaptabilities for the incompatible deformation, the resistance to bending is necessary to be checked when the measure of construction with the high plastic clay is adopted.