Mechanism Of Subgrade Consolidation With Gravel Pile

The research for gravel pile treatment of soft and weak subgrade has made a certain achievement and provided theoretical basis for the execution of many projects. This essay analyzes some mechanic features of grave pile, finding evidence from the gravel pile treatment of soft and weak subgrade in the construction of Qinhuangdao-Shenyang Passenger Line, and features of such treatment through indoor model test and in-site test. It also carries out the indoor test for the consolidation of railway soft and weak subgrade combining gravel pile method and grille reinforce method. The working mechanism of compounding subgrade and the comparison test for the load and variation features are also mentioned in this essay. Finally comes a conclusion of this essay that the load of the compounding subgrade increases in a certain degree, the settlement of soft and weak layer becomes relatively even and the maximum settlement correspondingly reduces by such flexible loads like road bank after setting gravel pile in the soft and weak subgrade. The consolidating effect of reinforcing mat towards the soft and weak subgrade is obvious, which seems like a flexible raft foundation with a certain anti-pull, anti-cut and anti-curve rigidity, making even the distribution of vertical pressure from super-structure to the top of the soft and weak subgrade and limiting the side variation. The effect of consolidating treatment of soft and weak subgrade combining gravel pile method and reinforcing mat method is obvious and playing a great role in increasing loading ability, reducing settlement and uneven settlement, stabilizing the subgrade and speeding up the construction. The more the mat layers in the grille-reinforcing mat, the better the consolidation. The position of the grille puts giant impact upon the consolidation of compounding subgrade and in this process, the grille shall place a lower place near the surface of such subgrade or above the ground level for better consolidation. Therefore what mentioned in this essay still needs verification with more tests and practices.