Study On Deformation Behavior Of Churning Mixing Stiffening Piles Supporting Applied In Soft Soil Excavation

Churning mixing stiffening piles is a new and initiative supporting structure. It combines the technical characteristics of mixing and high-pressure churning. It makes the cement and soil mixing more evenly and substantial increases the strength of the pile. Compared with ordinary supporting structure, the technology of construction process is simple, do not take up the excavation space and the cost is lower, the duration is shorter. Especially in terms of soft soil excavation, the anchoring effect exceeds ordinary bolt anchoring and soil nailing. It has been successfully applied to more than 100 excavations and the maximum supporting depth is 27m. However, the theoretical study of this new technology is still in its infancy. The anchoring mechanism for its soil is still being explored. The structural design main refers to the traditional design theory and method. It does not reflect the characteristics of the churning-mixing-stiffening piles supporting structure. Thus the further development and refinement of the technology is impeded. Based on this, the paper made the following research work:It is carried out the on-site basic test for Shanghai, Hangzhou and other typical soft soil. The result shows that the anti-pulling force reach to a higher level of stiffening piles in soft soil. And the deformation control of excavation slope get to the design requirement. Thus it is feasibility of this technology to apply in soft soil excavation. It summed up the deformation behavior of churning-mixing-stiffening piles structural system by analyzing the monitoring data of the physical construction. The application of this technology in soft soil excavation is key to the level of control over stress under the conditions of convergence of rheology of soft soil and pile-soil stress attenuation. As a basis, it is pointed out the stiffening skeleton effect principle of the stiffening piles. So it has made a theoretical guidance of the structure design. For the idea of deformation controlling design, we propose to estimate the largest settlement of the surface by the lateral deformation of the churning-mixing-stiffening piles supporting structure. And predict the settlement of the various points of the excavation surrounding by spoon-shaped distribution curve. Thereby we establish the method to evaluate deformation impact in excavation process. The case analysis shows that this method has a good engineering application value. Therefore, it has some significance and catalytic role for the development and application guidance of churning-mixing-stiffening piles excavation supporting structure of the paper.Figure 55 table 17 reference 54...