Model tests are performed on a vertical pile which is used as an anchor of an earth retaining wall. A rigid wall (b=1.6m, h=0.5m), which has hinge at its bottom and backfilled with dry sand, is anchored with an vertical pile (L=170cm, b=7cm) embedded in the backfill. Horizontal load is applied to the top of the wall, to give perfect active condition within soil mass behind the wall. Anchor pull, pile top deflection, and bending moment induced in the pile are measured at every in crement of the load.
　Test is repeated with four kinds of distance d between the wall and the pile, and the following results are obtained.
1. The effect of wall movement on the lateral resistance of an anchor pile is seen when d is smaller than a certain value, which is dependent on the conditions of pile, wall, and soil. The pile shows larger deflection and larger bending moment when d becomes smaller.
2. The Shinohara-Kubo method of lateral resistance estimation can be applied to an anchor pile when an idea of assumed ground surface is introduced.
3. Intersection of active rupture surface and passive rupture surface is considered to give the level of assumed ground surface. A good agreement is obtained between observed and estimated behaviours of the pile when the plane starting from the depth of lm1/3 along the pile is used as a passive rupture surface, where lm1is the depth of the first zero point of moment curve of a laterally loaded pile.