Study On Pore Pressure Of Sandy Soil

In recent years,due to the needs of social production and the rapid development of the national economy,the distribution of infrastructure projects has become more and more extensive.There are a lot of soft soil in many areas of our country,and it is easy to appear the problem of soft foundation in these areas.This kind of problem is particularly prominent in the offshore port engineering,but in order to better and faster engineering construction,we must solve the problem of soft soil foundation.The problem of soft soil foundation is that because of its high water content,high compressibility and low strength,it can not be used as foundation directly and must be treated by a series of measures.In the study of soil foundation,especially soft soil foundation,pore pressure often becomes an important factor of mechanical and deformation characteristics.The concept of pore pressure has been proposed for a long time.At present,pore pressure has been widely studied and applied in many fields.Pore pressure is divided into pore positive pressure and pore negative pressure,both of which play an important role in soft foundation consolidation,especially pore negative pressure,which is very important for soft foundation treatment.However,in the current research results,most of the researches focus on the positive pore pressure of saturated soil,few involve the specific research of pore negative pressure in natural state,and lack of equipment to accurately monitor pore negative pressure.At present,there are various problems in the pore pressure equipment used in engineering,and most of them can only be qualitative monitoring,and can not accurately monitor the pore pressure.Based on this problem,our research group designed and developed a new type of pore pressure device and improved it,so that it can carry out a complete indoor test.Not only the positive pore pressure of sandy soil can be accurately monitored,but also the positive and negative pore pressure of unsaturated soil can be accurately monitored.The group uses the self-developed device to carry out the pore pressure monitoring test of sandy soil indoor.On the one hand,the feasibility of the pore pressure device was verified,on the other hand,the existence of pore pressure was accurately monitored through the test,and the variation law of pore pressure in soil with free water level was obtained.At the same time,it is found that the peak value of negative pore pressure under plastic film is larger than that under plastic film;The analysis of the test data shows that there is a positive correlation between the layered settlement and the negative pore pressure,that is,the maximum settlement amount of the historical negative pressure soil is the largest,these laws are of great theoretical value for the problems of soft soil foundation in practical engineering.