Experimental Study On Liquefaction Behavior Of Reinforced-Soil

Liquefaction of saturated sand and silt is one of the important phenomenon of earthquake damage. Therefore, the problem of earthquake liquefaction of saturated sand has become an important research topic in geotechnical engineering. Vibration liquefaction, as the name suggests, is the liquid state condition and process of saturated soil which under vibrating load, the purpose is to limit liquefaction to occur and the development condition, to ensure the stability of buildings or the others ground. According to the United States of the America Geotechnical Engineering Soil Dynamics Committee in1978, the organization has extensively discussed the issue, and suggested that:" Liquefaction is process and role which make any material into a liquid. For no cohesion soil, this transition is from a solid state to a liquid state, it is the results of pore pressure increased and the effective stress reduced ". Liquefaction always has a great harm, so the liquefaction conditions, prediction and prevention have been become a major concern.In view of this, this article adapted the shaking table model test on reinforced soil which used the plastic screens, iron screens, Geo textile fabric and plastic woven fabric as reinforced materials, we has conducted a serious of reinforced soif dynamic characteristics test. Through the test, we had drawn some conclusions which through the macroscopic observation and test data analysis, it can be elaborated as follows:1) During vibrating test, for the foundation without materials reinforcement, from shallow to deep, the pore pressure ratio nearly reached1.10, it means entire layer liquefied. And the deep pore water pressure ratio is up to1.08, indicating that the lower part of the foundation have been liquefied entirely too. The deep pore pressure ratio is less than the shallow and middle, it means the liquefaction of shallow and middle are more heavy than top. In the view of time, the pore pressure of the shallow and middle firstly reached peak, it means the liquefaction starts from upper.2) For the foundation with plastic screens reinforcement, in the vibration process, the excess pore water pressures are increased with the depth, but the excess pore water pressure of superficial layer is the maximum, then the mid and deep. The pore pressure ratio of shallow reached1.27, completely liquefied; the pore pressure ratio of mid is1.10, and the deep is1.00, this mean the liquefaction has not started. From above of description, using plastic screens to reinforce the foundation, the anti-liquefaction capacity of foundation is improved overall, especially to increase the strength of middle and deep of foundation.3) For the foundation with iron screens reinforcement, in the vibration process, the excess pore water pressures are increased with the depth. The excess pore water pressure ratio of shallow reached Peak at1.07, liquefied completely. The excess pore water pressure ratio of shallow and middle layer are0.92and0.83, both were not reached1.0, the foundation has not yet been to be liquefied. So iron screens made the liquefaction ability increased, and improved the dissipation of pore water in the deeper soil. By using iron screens reinforcement, the anti-liquefaction capacity of the middle and shallow layer are improved largely.4) For the foundation with Sarong cloth reinforcement, during the vibrating test, the excess pore water pressures has increased with the depth. In terms of the pore pressure ratio, the superficial layer of the pore pressure ratio is0.77, it has not been liquefied completely. The central pore pressure ratio is0.66, and the deep pore pressure ratio is0.61, both were not reached1.0, the foundation has not yet been to be liquefied. Above of all, the Sarong cloth played an important role to improve the anti-liquefaction capacity of the foundation.5) For the foundation with Plastic woven cloth reinforcement, during the vibrating test, the excess pore water pressure also increased with the depth. In terms of the pore pressure ratio, the superficial layer of the pore pressure ratio is0.80, it has not been liquefied.The central pore pressure ratio is0.68, and the deep pore pressure ratio is0.63, both were not reached1.0, the foundation has not yet been to be liquefied. This means the Plastic woven cloth played a certain role to improve the anti-liquefaction capacity of the foundation. 6) Observing from the side of organic glass side and the surface of foundation, the effect of anti-liquefaction capacity which are reinforced with Sarong cloth is the best way.