Application Research Of Fine Sand And Silt

In engineering construction, often encounter water fine sand and fine sand pit or tunnel excavation, which is part of the silt layers has different collapsibility, generally this part of sand to maintain a low humidity in the natural water content in this case is generally can maintain a relatively high strength and compressibility will be relatively low however, when soaked in water, the strength will be significantly reduced, and the deformation rate will be increased, this property has a serious impact on the construction, often may occur even collapse or crack stratum deformation collapse, with collapsibility of sand disaster or other loss of the sensitivity of water for construction project in many areas. Because of this, want in the wet trapped sand area to build houses and no safety accident of construction, of silty sand soil collapsibility becomes particularly important. Widely distributed in the sand in China in northern Shaanxi, Gansu and other regions. The through laboratory consolidation test, penetration test method for geotechnical test and particle analysis on our part of the fine sand widely distributed regions of the foundation soil sample of undisturbed soil consolidation compression tests.Also the increased humidity, and decreasing moisture humidity test and adjustment, through the experiment, we can compare these regions sand collapsibility coefficient size, can also conclude the relationship between initial water content rate of the number and the collapsible deformation. The permeation experiments from the control of the porosity of sample, effect of contrast in different regions of silty sand porosity on the wet subsidence coefficient of that relationship of the permeability coefficient of the size and collapsibility coefficient. At the same time from the angle of liquid index of fine sand collapsibility study. Specimen under different liquid index and compression deformation amount and collapsibility coefficient between the relations, can the pressure is divided into strong, medium and weak sensitivity of the three stages, and in the actual construction process should be focused on pressure in sensitive and some fine sand liquid index is relatively small when sand moisture content changes of the sensitivity. This paper analyses the comparison of different pore ratio, under different pressure of soil water infiltration, wet depression of silty sand tests and engineering practice and got a good combination of. Finally, on the basis of North Shaanxi Shenmu Hengshan County and two multiple site of silty sand of physical tests compared in many academic predecessors of silt, fine sand and silty sand collapsibility based on the theory and practice of research summarized wet sand region of Northern Shaanxi collapsible regional variation, and points out that sand material composition composition and pore characteristics is caused by fine sand collapsibility of the root causes.Combined with engineering common foundation treatment methods will find silt eliminate collapsibility. After the acquisition of soil samples, brought to the laboratory for consolidation compression tests, before and after the treatment were studied. Soil collapsibility coefficient, and ultimately determine the foundation treatment of rationality, after strong ramming method and high pressure grouting method of foundation treatment, effectively control strata deformation, ensure the safety of working face stability and building and improve construction efficiency and reasonable to reduce production cost.