Research On Settlement Analysis And Prediction Of Composite Ground With Dry Jet Mixing Pile Of Highway

As a soil improvement technology , Dry Jet Mixing pile(DJMP) has many merits. With the rapid development of a great number of foundation engineering, it gets much wider application. However, application and development of this technology is great confined as academic research still lags behind practice. This article analyzes the deformation character and load transfer law of the DJM composite ground and discuss the factors which affect the settlement of composite ground through field test and FEM. At the same time, this article provides a simplified formula computing settlement and applies the gray theory to predict settlement of composite ground. The main contents are as follows:1. Based on the field loading test, this article analyzes the carrying capacity , stress distribution and the stress ratio of pile-soil of DJM composite ground. Accordingly the reinforced effect of DMJ is checked up.2. Applying ABAQUS, finite element method(FEM) is used to analyze the behavior of composite ground ,such as the distribution of the stress and deformation in reinforced regions and substratum. The law of load transfer between pile and soil is further revealed through the numerical analysis. At the same time, the factors, such as the stiffness and length of pile and replacement ratio in composite ground are discussed and so the best modulus of pile, the best length of pile and the best replacement are ascertained.3. Based on the existing literature and testing data, the side friction distribution was assumed triangle and a method to settlement of composite ground has been put forward. The key point is that the additional stress field should be obtained by applying both Geddes solution and Boussinesq solution. By calculating the real project, it is proved that the method has good precision and can be widely used in foundation engineering.4. Settlement of composite ground is predicted by using gray theory. The unequal time-interval prediction model of recent information of identical dimension for ground settlement is established in GM(1,1), and the buffered softening arithmetic is used to eliminate the infinite increase of the gray prediction model. Through the compare we can draw a conclusion that the gray prediction's precision is better than the double curvemethod and this method has great practical value in the settlement monitoring offoundation.