前言通过荷载试验(或横压试验)得到的P-S曲线,需要找出其比例界限点和极限荷重点,以供使用。但目前确定这两个界限点的方法,主要是直观判定,这就往往因人而异。凭直观确定这两个界限点,实际上是把P-S曲线按斜率的变化情况分为三段,使每一段内,斜率比较接近,段与段间斜率相差较大,以便直观上易于找到界限点。如果,我们按各级荷重间 Foreword P-S curve obtained by load test (or lateral pressure test), need to find out its proportional limit point and limit load point for use. However, the current method of determining these two limit points is mainly intuitive judgment, which often varies from person to person. By visually determining these two boundary points, in fact, the PS curve is divided into three segments according to the change of the slope, so that within each segment, the slope is relatively close, and the slope between the segment and the segment is relatively large, so that the boundary point can be easily found intuitively. . If we, according to each level of load