预应力锚索在加固重力式挡墙中的应用研究

The Application Study of Prestress Anchor for Retaining Wall Reinforcement Engineering

预应力锚索技术已在新建公路边坡开挖时得到了广泛应用,但在加固支挡结构且要同时保证其上方交通不中断条件下的应用研究极少见诸报道。以某互通匝道重力式挡墙加固工程为例,详细阐明了预应力锚索对重力式挡墙的加固机理,分析了挡墙的破坏模式,合理确定了锚索锚头的水平向、竖向间距,从而既保证锚固段端部不出现贯通的塑性区,又使锚索对挡墙的锚固力平均分布于挡墙体,能遏制挡墙的基底滑移和墙面开裂。采用了套管施工工艺,保证在预应力锚索成孔穿越墙背回填土层时,土层不塌陷,不影响成孔,进而确保墙顶车辆的正常通行。工程实例分析表明,该方法可靠,可据此对类似条件下的加固工程进行计算分析,尤其为加固工程的快速施工、保证通行的技术决策提供了一种切实有效的途径。

The application technique of prestressed anchor is widely applied to slope excavation in the highway engineering. While the study of prestressed anchor for reinforcing existing retaining engineering structures and ensuring uninterrupted traffic flow on top of the retaining structures has been reported rarely for recent years. Taking gravity retaining wall reinforcement project in a ramp of an expressway for example,the mechanism of reinforcement of prestressed anchor in the wall is introduced in detail. The failure mode of retaining wall is analyzed. The horizontal and vertical distance of anchor head are determined reasonably. This can not only ensure the plastic zone scope of anchoring section end discontinuous,but also can make the anchoring force of prestressed anchor to retaining wall body evenly distributed. The basic sliding and surface cracking of retaining wall have been effectively avoided. The construction technology of cast-in-place is used in the reinforcement project. The advantage of this technology include preventing the borehole from collapsing of wall back filling and speeding up the construction schedule while the prestressed anchor pass through the filling. Therefore,the construction of holes forming will cause any inconvenience to the top of retaining wall. And then the normal thoroughfare for vehicles is not been affected. The analysis of engineering example indicates： it is reliable to reinforcing gravity retaining wall and can be used for similar project while calculating and analysis. This method also supplies a practical way for decision-making of rapid construction and ensuring vehicle traffic in reinforcement project.