中文摘要：

为更真实地分析预应力锚杆复合土钉支护结构的侧壁位移变化规律，采用理论分析与现场实测相结合的研究方法，重点考虑预应力的施加对已施工土钉轴力的影响及产生的坑壁位移增量，对颇受争议的增量比例系数进行修正，并提出简化计算公式。研究结果表明，预应力的施加使得优势滑移面发生前移；上层邻近土钉的轴力变化较大；下层土体抗剪强度有所增加，土钉的约束作用将被限制。最后通过工程实例对提出的理论进行验证，证明计算结果的合理性和可行性。

英文摘要：

To analyze the horizontal displacement change of prestressed anchor composite soil nailing supporting structure more practically, an approach that combines theoretical analysis and field test was adopted. The research mainly focuses on prestress which affects axial forces of soil nails and causes horizontal displacements. The increment proportional coefficient which used to be an issue is modified, and a simplified calculation formula is proposed. The study indicates that prestress makes sliding surface move forward; that the axial forces of upper soil nails near prestressed anchor change a lot; that the shear strength of lower soil increases, and the constraint effect of lower soil nails is limited. A case is used to verify the proposed method and the results show that the method is reason-able and feasible.