加筋土边坡侧向变形对沉降和稳定性的影响

Influence of lateral deformation of a reinforced earthslope on its settlement and stability

大量工程实践表明 ,加筋土边坡的侧向变形与边坡的沉降和稳定性有着密切的联系 ,如何充分考虑和利用加筋土体侧向变形对边坡沉降和稳定的影响 ,是一个值得研究的课题。通过工程实例 ,阐述了加筋土边坡破坏的原因 ,并对边坡的稳定性及沉降进行了研究 ,指出加筋材料加固机理的实质是加筋材料与土体的位移协调一致 ,通过两者之间的作用 ,充分发挥加筋材料的抗拉强度 ,进而限制加筋土体的侧向变形 ,在某种意义上提高土体的抗剪强度 ,达到加固土体的目的。尽管极限平衡法不能直接考虑土体侧向变形对边坡稳定性的影响 ,但是 ,可以在该方法中通过调整土体强度指标的方法来间接反映这种影响。限制加筋土体的侧向变形 ,能够有效减少加筋土体的不均匀沉降和总沉降量 ,研究表明 ,不考虑侧向变形影响得出的沉降值小于实测值 ,其误差在2 0 %～ 3 0 %之间。

A number of engineering examples show that the lateral deformation of a reinforced earth slope has close relations with its settlement and stability.How to take account of and make use of the effect of the reinforced earth slope's lateral deformation on its settlement and stability is a subject worth being studied.Based on some case histories,the reasons for the failure of reinforced earth slopes are expounded,and their stability and settlement are investigated.The mechanism for the strengthening of earth slopes by using reinforcing material is that the reinforcing material and the earth mass can coordinately work due to friction between them,the tensile strength of reinforcing material is fully utilized to restrict the lateral deformation of the reinforced earth mass,resulting in increasing the shear strength of the earth mass in a sense,i.e.strengthening the earth slope.Though the effect of the lateral deformation of earth mass on the slope stability can not be taken directly into account in using the ultimate equilibrium method,this effect can be indirectly reflected by means of adjusting the strength index of earth mass.Restriction of the lateral deformation of reinforced earth mass can give full play to the tensile performance of the reinforcing material and decrease the non-uniform settlement and the total settlement.Research results show that the settlement taking no account of the effect of lateral deformation is less than the observed settlement,with their difference being 20%～30%.