Study On Compression Properties And Compression Prediction Model Of Nano-clay Modified Coastal Cement Soil

Coastal soft soil has the characteristics of high natural moisture content and high compressibility,which has become a core factor restricting the development of buildings in coastal areas.As the main method of strengthening soft soil foundation,cement soil has been widely used all over the world.Coastal cement soil has also become the main method of ground reinforcement in China’s coastal areas.When coastal cement soil is used as the foundation,its settlement is large,and it is necessary to conduct a consolidation test to study its compression characteristics.At present,the research on modification of the compression characteristics of coastal cement soil has become a hot issue in the construction industry.In this paper,the core properties of nanoclay,such as its filling properties,water absorption,swelling properties,and pozzolanic reactions,are used as the core,and these properties are used to modify the compression properties of coastal cement soils.This is done to reduce the compressibility of coastal cement soil.These studies have certain value for the application and promotion of coastal cement soil.The main research contents and results of this article are as follows:(1)The traditional consolidation sample preparation method was improved,and a bolt-type sample preparation method that does not consider the stress history and a hierarchical load-type sample preparation method that considers the stress history are invented.A high torque type demoulder was invented to demold the consolidated ring knife sample.(2)Under different curing ages,consolidation tests were performed on coastal cement soils with different cement contents to study their consolidation characteristics.The results show that the effect of curing age on consolidation characteristics is related to the cement content.There is a linear interval for the effect of increasing cement content on the compression of coastal cement soil.In this test,the cement content in this interval is within 12-18%.Considering it comprehensively,coastal cement with 18% cement content is preferred.(3)At different curing ages,consolidation experiments were performed on nano-cement soils with different nano-clay contents to study their consolidation characteristics.The results show that the increase of curing age can improve the consolidation characteristics of nano-cement soil,but different nano-clay content has different effects on the consolidation characteristics of the sample.When the content of nano-clay is 4% and 8%,the effect of improving the consolidation characteristics of the sample is better;when the content of nano-clay is 2%,the effect of improving the consolidation characteristic of the sample is poor;when the consolidation pressure is within [100,800] k Pa,nano-cement soil with a nano-clay content of 4% is preferred.(4)Micro-tests were performed on coastal cement soils with different cement contents and nano-cement soils with different nano-clay contents.The results show that the increase in cement content increases the aggregates in the sample;The effect of different nano-clay content on the sample is different,and the adhesion is better when the nano-clay content is 4%.When the nano-clay content is 8%,the filling property is better.(5)Based on the cosine function,the cosine-power function-exponential model is proposed,and the cosine-power function-exponential model is used to fit the measured data.Prediction models of the amount of compression of coastal cement soil and models of the amount of compression of nano-cement are established.