The Programmed Design Of Micropile Composite Anti-Slide Structure

Along with the development of the research on the landslide disaster prevention, engineering reinforcement measures have been to the direction of light-duty and miniaturization, micropile as a new type of slope retaining structure in engineering practice is more and more widely applied, which have got a good engineering effect and economic benefit. But the study of theory and procedural for the micropile composite anti-slide structure is also lagging behind, there is no mature calculation theory for the micropile which arranged obliquely or considered the earthquake action. Especially, there is no computation program for designning of micropile has be found in China. This paper based on science and technology project "research on the micropile composite structure design theory and engineering application" of China railway ErYuan engineering group, and the main results are as follows:1. The common micropile structure is classified into top type, slope foot and slope surface model, according to the micropile in the position of the landslide, and according to the connection form of the micropile structure can be divided into three types of micropile structure which include independent arrangement, frame connected and roof plate connected.2. The load calculation method of the micropile composite structure is given when the micropile composite structure is arranged obliquely or considered the seismic load. The landslide thrust is calculated by transfer coefficient method, whose direction is parallelling to the sliding surface. The landslide thrust should be decomposed into two directions of perpendicular to the pile and parallel to the axis of the pile when analyzed the inclined pile. When micropile composite structures used in the earthquake region, the earthquake force can be calculated by pseudo-static method. Taking pile top frame connected and roof plate connected, commonly used in engineering, as the research object, and the analysis model of theoretical calculation is established.3. On basis of the theory of elastic foundation beam, the displacement and internal force calculation theory is given when composite structure under different loads and different boundary conditions, according to the method of m+K and K+K. It is suggested that the load on the structure can be assumed as uniform load the method of m+K is used, and the load on the structure can be assumed as triangular distribution the method of K+K is used, when the structure designed and calculated. General steps for designning of the micropile composite anti-slide structure is proposed based on the contrast of two calculating methods.4. On the basis of theoretical analysis, the micropile composite structure design and calculation program is written by Visual Basic6.0. and a series of function can be realized by the program, such as parameter inputâ†'internal force calculationâ†'results check (calculations and graph)â†'structure checkingâ†'automatic drawing CAD files and so on. The implementation method of each modules are presented detailedly. and the correctness of calculation results from the calculation program is verified through combining with the existing prototype test results of micropile.