Study On The Horizontal Displacement Test Of Liquefiable Sand Soil Foundation Model Reinforced By Pile

The earthquake happened frequently for recent years at home and abroad, which endangered people’s life and property safety. It is the secondary disaster of earthquake for the saturated sand under earthquake load vibration to be liquefied and it leads to a large of area damage of buildings. Therefore, reinforcement qualified soil is an important research subject in the area of geotechnical engineering. After years of indoor research and outdoor engineering practice, geotechnical engineer found that flexible pile such as gravel pile, etc. can dissipate pore water pressure in soil in the process of earthquake, and compact the soil, which has better liquefaction resistance effect. However, the rigid pile such as steel tube pile can improve the vertical bearing capacity of soil to strengthen the horizontal shear performance of the foundation, but it has no obvious effect for the inhabitation liquefaction. It has fewer researches about how to design the pile body of existing and controlling the liquefaction, at the same time to improve the vertical bearing capacity of soil and horizontal shear performance of the foundation, which should has in-depth exploration. Therefore, it has significant meaning to design and research the ravel filling the core steel tube pile reinforcement mechanism and liquefied soil reinforcement effect and the foundation level of resistance force characteristic as a whole.This paper relies on the National Natural Science Foundation of China (Grant No.50578104)"Liquefied Sand Pile Reinforcement Mechanism of Experimental Research," and the highway construction area of Shanxi Province Key Laboratory of Loess and Maintenance Technology Project (Contract No. KLTLR-Y13-3)"Experimental Study of Liquefied Soil Pile Foundation", mainly about the designed different type of pile bodies reinforcement foundation to have the shaking table test under the action of horizontal load to analyze the unreinforced foundation, gravel pile reinforcement foundation, steel tube pile reinforcement foundation, macro phenomenon gravel filling the core steel tube pile reinforcing foundation and The corresponding super static pore water pressure, earth pressure, horizontal displacement time travel curve. After collecting and counting each group peak value and60seconds corresponding value along the depth change, the conclusions as below:(1) Macro phenomenon of model foundation test can be seen: unreinforced foundation has the liquefaction as a whole from deep layer to shallow layer; the displacement of middle pile is obvious. During the vibration of gravel pile reinforcement foundation, water flows from the gravel pile. In the process of the test, gravel pile becomes the drainage way to make the water in the soil drain to the foundation surface and the water submerges the pile block. After vibration load of steel tube pile reinforcement foundation, water body is collected around the pile. After test, it is found that there is a large number of water in deep soil and the pile has little displacement. In the process of vibration, gravel filling steel tube pile drains parts of water body; there is still a large number water body in the ravel, and it is hard to dig the foundation oil body compaction.(2) From the pore water pressure of model rest, it can be seen:for each group, the pore water pressure increases with the buried deeper. The pore water pressure unreinforced foundation at12cm,24cm and36cm is larger than another three reinforced foundation. Gravel reinforcement foundation and gravel filling steel tube pile reinforcement foundation pore water pressure appear various reduce after reaching the peak value, which explain that gravel pile and gravel filling steel tube pile have the advantage of dissipate pore water pressure, and the drainage effect of gravel pile is better than gravel pile filling pile, which declare that the gravel filling pile has the characteristics of steel tube pile and gravel pile on the liquefaction resistance.(3) Earth pressure for each group test appears that the middle is large and shallow and deep layer is small. The gravel pile and gravel filling pile drains water from the earth to make the earth body more compacted and strengthen the earth strength. During the middle and later periods of test, steel tube pile reinforcement foundation earth pressure curve appears horizontal extending, which explains that steel tube pile reinforced not only inhibits the soil pressure mutations, but also improves the horizontal shear force of foundation soil as a whole.(4) Horizontal displacement of piles reinforced composite foundation from small to large:gravel filling pile, steel tube pile and unreinforced. Integrated each group test, we can find from soil pressure and pore water pressure:small pore water pressure and large soil pressure make the displacement small. Soil body becomes more compacted and the displacement between piles becomes smaller with the water body drains in the soil.(5) In conclusion, gravel filling steel tube pile not only has high bearing capacity at the vertical, but also reduces a certain number of pore water pressures to improve soil pressure and strengthen soil body strength. Besides, it has small displacement during vibration and improves horizontal bearing capacity of foundation. Therefore, it is feasible to reinforce the liquefied soil in the practical engineering with its good engineering characteristics.