Experimental study on lateral pile-soil pressure on passive part of pile groups in innovative sheet-pile wharf

The pile group of vertical cast-in-place piles with relief platform has been successfully introduced into innovative sheet-pile wharfs to withhold lateral load due to horizontal soil movement along with its front wall. The work mechanism of the piles is similar to that of stabilizing piles, but their pile-soil interaction degree is far below the limit state. In order to study the distribution of the lateral pile-soil pressure along pile for the formation of its design method, geotechnical centrifuge model tests of two schemes are conducted to simulate 200,000-tonnage sheet-pile wharfs with relief platform in fine sand. The pile-soil pressure distribution is obtained by measuring the earth pressures at its two sides. The characteristic is that the lateral pile-soil pressure is positive for the upper part, meaning the same direction to soil movement, and negative for the lower part. And the position of zero value of pile-soil pressure is below the mud line of harbor basin by about four times the pile diameter. By using the position of zero pile-soil pressure as the demarcation line, each pile can thus be divided into the upper passive part and the lower active part, as is done in stabilizing piles. In order to estimate the pile-soil pressure of pile's passive part, it is correlated with the Rankine active pressure by introducing an average breadth ratio on the passive part of pile. It is found that the breadth ratio of pile's passive part is about 3.0 for seaside piles, much bigger than that for the middle and landside piles. Therefore, the pile-soil pressure of pile's passive part can be taken to be 3 times the Rankine active pressure in the design of pile groups with relief platform.