Abstract：In order to define the strain ranges, four groups of laterally static load tests of single pile under different depth of pile foundation were carried out by a three-dimensional physical simulation loading system. The concepts of maximum strain sectional area S0 and maximum strain distance L were introduced by collecting the soil pressure data in front of the pile. Based on the existing strain wedge model, the variation of soil strain range around pile with the lateral load and embedded depth of pile foundation could be calculated by the formula.The curves of displacement-load and displacement-depth at pile top were obtained by experiments. It was found that the strain range and the maximum strain distance of the soil around the pile turned out a nonlinear increase of the S-type function with the rise of the lateral load and the nonlinear decrease of the exponential type function with the rise of the embedded depth of the pile by theoretical calculation, and the strain range and the maximum strain distance showed good coordination with the change of the load grade and the embedded depth of pile foundation. When the process of stress and strain of pile and soil entered the plastic stage or the embedded depth of pile foundation increased to a certain extent, the range of soil strain tended to be stable gradually.The function relationship between the maximum strain distance L and the embedded depth of pile foundation were proposed, which provided a reference for the selection of pile foundation placement.

Keyword：pile foundation;lateral static load test;strain range of soil;wedge model;embedded depth;