摘要:
为在特高压输电线路桩基础中推广PHC抗拔管桩,考察混凝土填芯与管桩内壁黏结面抗拔承载性能,完成了6根PHC 600 B 130抗拔管桩的混凝土填芯轴拉室内足尺试验。试验中考虑了不同的填芯长度和管桩内壁界面处理方式,得到了轴拉力试验值、界面平均黏结强度、界面黏结系数和滑移量等试验结果。结果表明:各试件的最大轴拉荷载试验值总体上随填芯长度的增大而线性增大。填芯混凝土界面全长平均黏结强度试验值介于0.603~0.774 MPa之间,填芯长度和界面处理方式对试验结果的影响均较小。沿管桩填芯全长,各截面上填芯混凝土界面黏结强度和滑移量均为靠近加载端大,远离加载端小,靠近加载端的填芯混凝土承担了更大比例的轴拉荷载,填芯混凝土界面全长平均黏结强度设计值可取0.30 MPa。
Abstract:
In order to popularize PHC uplift pipe pile in UHV transmission line pile foundation, the uplift bearing performance of the bonding surface between core concrete and the inner wall of pipe pile was investigated. The full-scale tests of 6 PHC 600 B 130 uplift piles were completed. In the test, different core filling lengths and interface treatment methods of the inner wall of the pipe pile were considered, the test results of axial tension, average bond strength of the interface, bond coefficients of the interface, and slip were obtained. The results showed that the maximum axial tensile force of each specimen increased linearly with the increase of core length. The average bond strength test value of the whole length of the core filled concrete interface was between 0.603 MPa and 0.774 MPa, and the core filling length and interface treatment method had little influence on the test results. Along the whole length of the pipe pile core filling, the bond strength and slip of the core filling concrete interface on each section were larger near the loading end while smaller away from the loading end. The core filling concrete near the loading end bears a larger proportion of axial tensile load. The design value of the average bond strength of the whole length of the core concrete interface could be taken as 0.30 MPa.