Study On Shear Creep Behavior Of Fiber Solidified Soil From Dredged Sediment Of River And Lake

Dredging is a necessary process for the development,expansion and maintenance of ports,ship ports and various waters.Every year,a large amount of dredged sediment is treated as waste,causing serious environmental problems.It is of great significance to solidify and improve the dredged sediments of rivers and lakes to realize the recycling of waste soil resources.On the one hand,it can alleviate the lack of dumping sites for dredged sediments of rivers and lakes and help reduce its pollution to the environment;The solidified soil of the dredged lake bottom mud is used as a roadbed filler or building material.Therefore,governments of various countries including our country have begun to attach importance to the resource utilization of silt,which can not only effectively treat the dredged sediment,but also generate considerable economic benefits and contribute to the sustainable development of our country.At present,there are few studies on the shear creep characteristics and long-term strength of fiber-solidified soils from dredged rivers and lakes,and the influence of structural strength is not considered in the construction of creep constitutive models and long-term strength calculation equations.The engineering application of dredged bottom mud fiber solidified soil lacks theoretical reference.In this paper,a direct shear creep test is conducted on fiber-solidified soils of dredged sediments from rivers and lakes,and the structural strength is incorporated into the construction of the constitutive model and long-term strength calculation equation of the fiber-solidified soils of dredged sediments from rivers and lakes.1.The formula of fiber-solidified soil used in the experiment was obtained by orthogonal experiment.After the preparation of all soil samples,the water content was 68.2%,and the difference in structural strength was controlled by a small difference in cement content.Because all soil samples only have a small difference in cement content and the mixing amounts of other materials are all the same,it can be considered that the composition of the soil samples is similar.2.A series of laboratory tests were carried out on the fiber-solidified soil of dredged mud from rivers and lakes.The physical and mechanical properties of the fiber-solidified soil,such as compression and shear characteristics,were analyzed and researched.The test results showed that the structural strength has a greater impact on the basic mechanical properties of the soil.3.Using LFTDZJLBY-I automatic direct shear creep tester,the shear creep test of fiber-solidified soil of river and lake dredging mud under different vertical stresses was carried out,and according to the shear creep of fiber-solidified soil of river and lake dredging mud Based on the test results,draw the shear strain-structural strength isochronous curve,shear stress-strain isochronous curve and shear modulus-structural strength isochronous curve,and analyze and study them.4.From the perspective of soil non-linear creep,the shear creep characteristics of fiber-solidified soil are studied,and a semi-theoretical and semi-empirical creep constitutive model considering the structural strength is constructed,This model has strong applicability to different fiber-solidified soils.5.By selecting the long-term failure criterion,a long-term strength prediction model of fiber-cured soil in the form of a power function is established.Comparing the long-term cohesion and long-term friction angle of fiber-cured soil with the instantaneous cohesion and instantaneous friction angle,it is found that the long-term cohesion of fiber-cured soil decreases and the long-term friction angle increases.