池州长江公路大桥根式基础承载力试验研究

为了解根式基础主体结构及根键的承载能力,以池州长江公路大桥南岸引桥(36×30m预应力混凝土连续箱梁桥)为依托,针对S10号墩的根式基础开展静载试验。分别采用自平衡法和堆载法测定基础的极限承载力和桩身侧摩阻力,根据测得的各土层摩阻力计算根键所承担的荷载,并将试验结果与《根式基础技术规程》(DB34/T2157-2014)中的简化公式计算结果进行对比。结果表明:自平衡法测得的单桩总承载力为28146kN,其中根键承担5265kN;堆载法测得的桩身侧摩阻力为15200kN,其中根键承担4895kN;根键承担了较大部分的承载力,能大幅提高基础的承载能力;试验测得的单桩总承载力、桩身侧摩阻力和根键承载力均远大于根据规范简化公式计算的值,计算结果偏于安全。

Experimental Study of Bearing Capacity of Rooted Foundation for Chizhou Changjiang River Highway Bridge

In order to study the bearing capacities of main structure and roots of rooted foundation, static load tests were performed on the rooted foundation of pier S10 for South Approach Bridge of Chizhou Changjiang River Highway Bridge which consists of 36×30 m prestressed concrete continuous box girder bridges. In the tests, the self-balancing method and preloading method were employed to measure the ultimate bearing capacity and side friction resistance of the rooted foundation. The load borne by the roots were calculated based on the measured friction resistance of each soil layer. Then the test results were compared with calculation ones according to the formulas given by Technical Specification for Design and Construction of Rooted Foundation (DB34/T 2157-2014). The results show that the total bearing capacity of single pile measured by the self-balancing method is 28 146 kN containing 5 265 kN loaded by roots;meanwhile, the total side friction resistance measured by the preloading method was 15 200 kN containing 4 895 kN loaded by roots. Thus the roots bear a large part of the bearing capacity, and are effective to improve the bearing capacity. Moreover, the tested values of bearing capacity and side friction resistance of single pile as well as the bearing capacity of roots are far greater than the calculated values calculated by the simplified formulas in the specification, indicating that the calculated results have a higher tolerance.