Study On The Influence Of Water Content On Shear Behavior Of Soil Anchored By Soil Nails

Soil nailing reinforcement is one of important forms for soil anchoring.Soil water content has an important influence on soil mechanical properties of soil without anchoring(pure soil)and anchoring soil with soil nail.In this paper,a device is developed to make anchoring soil specimens with soil nail,which is used to carry out direct shear tests of anchoring soil with different water content.The specimens are observed and analyzed by electron microscope.The soil water content influence on shearing resistance performance of soil without anchoring and nail anchoring soil is quantitatively analyzed.The water content range in which improves shear strengthening with soil nailing is determined,and the shear strengthening mechanism of soil nailing is developed.The results show that:(1)Soil nailing can influence the shear strengthening effect in a certain range of soil water content.When the soil water content is out of this range,the shear strengthening effect of soil nailing gradually weakens,even fail.The range of soil water content that is beneficial for the shear strengthening effect of soil nailing is 15%-22%.(2)Soil water content will affect the particle arrangement structure of soil after compaction.The phenomenon of dilatancy is beneficial to the formation of local strengthening zone,which promotes the shear reinforcement role of soil nailing.(3)The fitting formulas between water content and cohesion c,as well as between water content and internal friction angle φ of soil and nailed soil are established.(4)The fitting formulas between water content and c,φ are applied to a foundation pit engineering for numerical calculation.According to the calculation results of different water content conditions,the influence of water content on the foundation pit stability with soil nailing is analyzed.