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结合某黄土斜坡桥梁桩基工程,对同一坡度相近位置的两根桩基开展现场试验,研究其在不同竖向荷载工况下的桩身上、下坡面两侧的轴力、桩侧摩阻力及桩侧土压力的传递规律与分布特征。试验表明:桩基荷载传递具有明显的区域性,第1区域是从桩顶至约3倍桩径深度处,此区域上坡面桩侧轴力较下坡面相应位置小,且其轴力随深度递减幅度及侧摩阻力发挥程度均较下坡面桩侧大;第2区域是从约3倍桩径至10倍桩径深度处,桩身上坡面一侧竖向受力减小幅度小于桩基下坡面一侧,但此时下坡面桩侧摩阻力发挥幅度大于桩基上坡面一侧;第3区域是从约10倍桩径直至桩端,该区桩身两侧轴力差异不大,摩阻力发挥幅度相近,荷载平衡协调且向下传递稳定。针对斜坡桥梁桩基上、下坡面两侧所受土压力的不均匀性,对设计桩基竖向承载力进行了一定程度地折减,并对计算公式作了相应修正,研究结论可供类似工程参考、借鉴。
Combining with the pile foundation engineering of a certain loess slope bridge, two pile foundations with the same grade are tested in field to study the axial force and the pile side frictional resistance on the upper and lower sides of the pile under different vertical load conditions And earth pressure on pile side of the transmission law and distribution characteristics. The test results show that the load transfer of the pile foundation is obviously regional. The first area is from the top of the pile to about 3 times the depth of the pile. The axial force of the pile on the uphill surface in this area is smaller than the corresponding position of the lower slope, The second area is from about 3 times of pile diameter to 10 times of pile diameter, and the vertical force reduction on the upper side of the pile body Less than the side of the pile bottom slope, but this time on the lower side of the slip pile lateral friction greater than the pile slope on the side; the third area is about 10 times the pile diameter until the pile end, Force is not very different, friction similar to the extent of play, load balance and coordination down the transfer of stability. Aiming at the inhomogeneity of soil pressure on both sides of the upper and lower slopes of pile foundation of slope, the vertical bearing capacity of designed pile foundation is reduced to a certain degree, and the formula is corrected accordingly. The conclusions are available Similar engineering reference, reference.