Study On The Application Of Soil Nailing In Soft Soil Slope

Soil nailing is more and more widely used in soft soil ground in our country in recent years. However, the mechanism of soil nailing for soft soil slope wasn't understanded completely, it's design theory lagged behind the engineering practice. The support mechanism of the pre-retaining structure and composite soil nailing for soil nailing in soft soil ground are discussed based on the past researches.The main contents of the thesis are as the following:The engineering geological conditions of the projects that are suitable to soil nailing in soft soil ground successfully in our country in the recent years are summarized. And the physics and mechanics characteristics of soft soil that are suitable to soil nailing is suggested.The theory of earth pressure acting on piles in a row is applied, which has already been derived by Ito and Matsui, to analyze pre-retaining structure. The working principle of pre-retaining structure used for major anti-sliding measure and soil arching effects are discussed. According to the failure forms of soil nailing system with pre-retaining structure, the stability analyzing method for soil nailing system with the pre-retaining structure is suggested.The failure forms, operation and deformation mechanism of composite soil nailing are summarized. The anti-seepage stability, anti-heave stability and overall stability of composite soil nailing are discussed. The shearing force balance method in anti-heave stability analysis of composite soil nailing is presented, and accurate calculation formula is deduced. Based on the theory of elastic foundation beam, the shotcrete-layer of a combination of soil nails with waterproof cement-soil mixing piles is studied , and it's formula are derived from different situations.The design method, construction technology and construction requests of soil nailing for soft soil ground are summarized.