Study On Application And Stress-Strain Properties For Cemented Coarse-grained Soil

Cemented coarse-grained soil is a stone material, which is take advantage of natural (or through the simple process of) sand and gravel, excavated materials or other easily accessible rock materials (including the low strength materials that conventional concrete can not use), and compacted by adding an appropriate amount of mixing water and cement materials. As a new material, cemented coarse grained soil has merit of low energy consumption, conserving resources and protecting the environment, etc., but also has high strength, strong fire-resistant, seismic performance and other safety performance. Therefore, it have broad application Prospects in the field of civil engineering and water conservancy projects.Compared with the coarse-grained soil, study on mechanical characteristics of cemented coarse-grained soil 1 is rare. Study on properties of materials of CSG mechanical has lagged far behind the actual engineering. It was usually assumed to be elastic-plastic materials and only consider the elastic range and the material models use linear elastic model in design, calculation and analysis process. In fact, CSG has the materials characteristics of both coarse grained soil and concrete, and its mechanical properties is between them. the strength and stiffness are lower than concrete, but much higher than the soil of stone. In the present, the research results on coarse grained soil and concrete can not be directly used for cemented coarse-grained soil, it needs for specialized research on mechanical properties of materials of cemented coarse grained soil. Therefore, through a large number of triaxial tests of CSG cementation mechanism, characteristics of deformation and strength and influencing factors, to strengthen measures for improvement, analysis on stress and deformation was studied in this article.This paper firstly has studied the Influence factors of cement content, confining pressure, and age on deformation and strength characteristics of cemented coarse grained soil. The results show that the coarse grained soil cement is a typical strain softening material; with the cement content increases, the peak strength of the material was improved, but residual strength did not change significantly; both peak strength and residual strength improved with the increase of confining pressure and age.Then this paper has also studied the influence of polypropylene fiber including its content and length on deformation and strength characteristics of CSG. The results show that after adding polypropylene fibers to the sample, the peak strength improved not obvious, but residual strength markedly, brittleness index decreased. The peak and residual strength did not change significantly when the cement of polypropylene fiber is 1%-2% and its length is 6mm-19mm.Finally, using Coulomb strength criterion, the result parameters of the various test conditions was finished and the changes of parameters was summarized, which provided evidence for the further development of stress-strain relations of sands cemented model. In addition, the article also assumes different conditions that through the use of cement and non-cemented coarse-grained in homogeneous soil dam. by comparation and analysis on safety factor of stability, the conclusion is that cemented coarse-grained soil materials can significantly improve the stability of the dam.