Research on Model Tests of the Additional Stress in Soil Caused by Pile Loads

To study the distribution of the additional stress in soil under various loading modes, micro earth pressure gauges are buried at different positions from the horizontal direction of a pile body and at different depths in the vertical direction, and model tests of the top-loaded pile (with soil under the pile and without soil under the pile), the bottom-supported pile, and the O-cell pile under the same conditions are carried out. The results show that the additional stress in the soil increases with increasing load on the pile body and shows a linear distribution. Under the same load, the additional stress of the top-loaded pile is greater than that of the bottom-supported pile. The value of the additional stress in the soil at a distance of 1.7d from the horizontal direction of the pile body is relatively large, while that at a distance of 4.5d becomes very small, which is only 1/14 to 1/10 of that at 1.7d. In the depth direction, the distribution of the additional stress in the soil of the pile under the top-loaded mode is an inverted triangle, while that under the bottom-supported mode is a triangle. The top-loaded pile shows a loading effect on the soil in the range of 4.5d, and the bottom-supported pile shows an unloading effect. Under the condition of the O-cell test pile, the loading effect of the lower section pile on the bottom soil of the pile is greater than that of the traditional static load test.