Analysis Of Soil Compacting Effect Of Pile Group

With the continual growth of the national economy, the number of high buildings is increased day by day especially at the coastal cities. Jacked pile is now widely used because of its various advantages, such as its high quality, easy settlement, lower cost, and no pollution of noisy and slurry, etc. Jacked pile is widely used in Tianjin with ten million meters constructions in these years. But the obvious compacting effects caused by the penetration of jacked pile may have severe influence on surround engineering environment. So it's important for engineering application with the analyze of compacting effects of jacked pile.This paper is based on the soil of Tianjin and the Science and Nature Fund of Tianjin—The Study and Countermeasure of Soft Soil Macro-mechanical of Soil Compacting Effect ,a jacked pile group model test is made ,some work are made as follows.1. Based on jacked pile model tests of one or two or three piles pressed into clay, the horizontal and vertical displacements are measured and analyzed. The laws of soil displacements changing with horizontal distance in the soil and vertical distance at the surface of soil during the process of pressing piles are obtained. We discovered that it's important for the increase value of the horizontal and vertical displacements with the different driving order. The horizontal and vertical displacements are accumulated during the pile group pressed into clay, and this is important for the engineering which we can't ignore its effects.2. Based on jacked pile model tests, the excess pore water pressure which was made by the pile group is measured .The change of excess pore water pressure is very complex after the pile group pressed into clay, and as the increasing number of the piles pressed into the clay the excess pore water pressure is also increasing, to some extent, the value of the excess pore water pressure is slow down to a stably value.3. Based on jacked pile model tests, other relative experiments are also made, the change of physics and mechanical property after pile group pressed into clay is analyzed.4. Because macro-mechanical property of soil is the reflection of micro-structure variation, to study the structural constitution of fore-and-aft pile group pressed into clay, electronic scanning microscope is used to obtain the microscopic scanning picture of model test soil, and picture processing software is used to obtain the micro-structure parameters. Then the soil compacting effect dues to the micro-mechanism was discussed in this paper.