Loess Areas Of Deep Foundation Pit Supporting Structure Analysis And Design Software Development,

Aimed at some problems existing in design of retaining and protection structure of foundation excavations at present, such as complexity, slow speeds, zonal differences and so on, and according to research findings about the technology of retaining and protection of foundation excavations in recent years, and in order to improve utility research on retaining and protection of foundation excavations in loess zone, in this paper, some design methods, which are suitable for the structure of retaining and protection of foundation excavations in loess, are generalized and improved, and one new design software are developed, which is characterized by friendly interface, easy operability, calculation accuracy, and good commonality.According to the geotechnical characters of loess in northwest of China and many design experiences for practical project, several retaining and protection structures, such as the structure of cantilever pile , the single support structure of pile-anchor, the soil nailing wall and the structure of frame retaining wall with anchor, are suitable for foundation excavations in loess. According to Technical Specification for Retaining and Protection of Building Foundation Excavations—JGJ120-99, the design methods of above structures are summarized, generalized and improved as follow aspects: First, the design methods of structure of cantilever pile and pile-anchor are generalized and analyzed. Second, based on the design methods of present Specification, the methods of stability analysis of soil nailing wall are improved. The new research model of the most dangerous sliding surface are set up, and the region of centre of circular slip surface is determined dynamically by computer, and stability of soil sailing wall at each excavation stage is analyzed timely. Third, for the structure of frame retaining wall with anchor, the design methods are improved, matrix displacement method is used in the calculation of column moment, and the stability analysis method of frame retaining wall with anchor is derived according to the stability analysis method of soil nailing wall.Based on the above generalization and improvement on retaining and protection structure of foundation excavations in loess, and Using Object-oriented programming Language VC++ and MFC, design software for soil nailing wall is developed. For the development of this software, there are several parts as follows: demand analysis, general structure design, model design, the design of man-machine interactive and user interface, code compile and so on. In the calculation of frame retaining wall with anchor, the interface technique between VC++ and Matcom library is used to solve the matrix calculation, so that the efficiency of software development get increasing greatly. Finally, many practice projects are calculated and designed by this software, and the accuracy, operability and practicability of this software is verified. At the same time, the user's guide of this software is finished, which will help to generalize the application of this software in the design of practice projects.