Study About Liquefaction Mechanism And Reinforcement Of Sand In Some Area Of Zhoushan

It is easier for the saturated sand to liquefy under the vibration of the earthquake,which will result in water spraying and sand emitting,uneven foundation settlement and ground cracking and so on.It will always bring a great loss to the possession and life of human beings.Meantime,due to the complexity and the regional character of soil,there are the different liquefaction mechanisms of sand in the different regions as the earthquake happens.Thus,it is meaningful to carry out the analysis of the liquefaction mechanism and the reinforce measures for the sand foundation in a special area.In this thesis,the sand in a special area of Zhoushan is selected as the study object,and the following tests are designed and carried out by a shaking Tab.,which includes the unreinforced saturated sand model,the gravel pile strengthening model with 3 times pile spacing,the models with 4 times and 5 times pile spacing.After observing and comparing the macroscopic phenomenon of each model,the datum of the excess pore water pressure and the acceleration of each model are collected and analyzed by using the relevant software.The experimental results show that:(1)From the macroscopic phenomenon of the sand liquefaction to view,there are some clear differences between the unreinforced and the reinforced sand models.For the unreinforced sand model,the pore water firstly permeate out of the surface crack of the soil along with the surface bump of soil,while for the reinforced sand model the pore water begins to emerge from the gravel pile without any bump on the surface of soil.Thus,it can be found that the gravel pile plays an important role for effectively dissipating the pore water.(2)For either the unreinforced model or the reinforced model,the excess pore water pressure will increase with the depth of sand.The peak values of the excess pore water pressure will be similar in the same depth for the different sand models.(3)The gravel pile strengthening model with 3 times pile spacing is the most effective for liquefaction resistance among all of the designed models.That is to say,the initial time of liquefaction of the saturated sand will be much later for the model with 3 times pile spacing than the other models.The results will be helpful for the foundation treatment resisting the liquefaction of the saturated sand in earthquake,and it can also provide a useful reference for the relative engineering application.