For over-length and large-diameter bored piles with dense distribution

especially for high-pile group

in the solidification process pile concrete brings intensive compacting effect on soil around the pile. It is significant for enhancing integrity and bearing capacity of pile group

and controlling settlement of the foundation. The purpose and scheme of the test are designed according to the super-large pile group foundation of Sutong Bridge. The test gives the distribution and change laws of lateral compacting pressure. It is shown that the lateral compacting pressure increases continuously after pouring the pile

especially for the concrete in flow-plastic before initial set

the increase amplitude is 8.4 to 13.5 percent. The lateral pressure still keeps 0.8 percent of increase from initial set to the 14th day of the test.