钢筋在堆石料中的拉拔试验研究

作为一种有效的土石坝抗震加固措施，加筋在高土石坝建设中正被越来越广泛地运用。钢筋与堆石料接触特性及影响因素研究是合理进行加筋设计的前提。通过室内拉拔试验研究了钢筋与堆石料的界面摩擦特性，揭示了不同上覆压力、堆石料含水状态、堆石料级配及孔隙率等因素对试验结果的影响。结果表明，堆石料与钢筋接触面剪应力与拉拔位移曲线呈下端开口的抛物线形状，上升段陡于下降段，残余剪应力数值不稳定；4个影响因素中，上覆压力与峰值剪应力曲线近似于线性正比关系；孔隙率和峰值剪应力曲线类似于线性反比关系；级配平均线的峰值剪应力与拉拔位移曲线位于级配上包线的试验曲线之上；饱和含水状态下堆石料的峰值剪应力与拉拔位移曲线远低于风干状态。

Pull-out test analysis of steel bar in rockfill materials

As an effective seismic strengthening measure for the earth rock dam, the reinforcement is used more and more widely in the construction of high earth rockfill dams. A premise of the reinforcement design is the research on the contact characteristics and influence factors of the steel bar and rockfill materials. The authors of this paper, through laboratory pull-out tests, made studies of rebars and interface friction characteristic of the rockfill materials, and revealed the impacts of different overburden pressures, water content of rockfill, aggregate gradation and porosity factors on the test results. The experimental results show that the rockfill materials and steel contact shearing force and pull-out displacement curves show a parabolic shape with an opening at the lower end, which is steeper than that in the descending section, and the values of the residual shear stress are unstable. For the four influence factors, the overburden pressure and peak shear curves have approximately linear relationships; the porosity and the peak values of the shear curve are similar to a linear inverse relationship; the peak shear stress and the pull-out displacement curves of the trim level average are over the test curves of the grading of the upper envelope line. The peak shear stress and the pull-out displacement curves of the rockfill materials under the conditions of saturated water content are much lower than those under the dry conditions.