Stress-deformation Analysis Of Surge Shaft Caisson Of The Xier Ditch Hydroelectric In The Construction Process

As a form of foundation, caisson has a very wide range of applications in the underground structure and deep foundations, which owns the advantages of small construction footprint, wide range of soil,construction of great depth,small impact on the surrounding environment as well as low construction cost. Therefor, due to the complexity of geotechnical engineering as well as the uncertainty of the caisson structure in construction, how to ensure the caisson's sinking safely and smoothly in different geological conditions has become an engineering difficulty and there is not a mature theory and numerical simulation that we can draw. With the universal application of caisson in the construction, the research of caisson construction is particularly important.Based on the above research background, caisson structure of surge shaft of the Xier ditch hydroelectric as the research object, the stress and deformation of caisson wall and foot blade were analyzed particularly in different sinking depths, and a reasonable excavation recommendations was proposed to ensure the safety of caisson structures in the construction. Build in deep cover layer, which has a number of large size boulders, caisson construction is enormous difficult. In response to this characteristic, in this paper, several typical operating conditions were divided to analyze the impossible encountered situation in the sinking process of caisson. Main research contents are as follows:â‘ Point to the uncertainty of the distribution position and the number of boulders, the form of support under the caisson foot blade may be considered into several situations(caisson foot blade supported by a homogeneous soil,caisson foot blade supported by 1-3 boulders and soil), on this basis, the impact of the amount of soil excavation at the foot on the stress of caisson structure was analyzed.â‘¡Considering the situation that the overall offset of caisson may occur in the process of sinking lead to the de-empty situation between the caisson wall and the surrounding soil. Therefor, the empty situation was simulated in the calculation, and the stress- deformation of caisson construction was analyzed at the different empty section in the sinking process.â‘¢Friction coefficient sensitivity of sand gravel layer of caisson surrounding was analyzed, and the variation of caisson displacement and stress were compared with different friction coefficients.In this paper, finite element software ANASYS was used as the method of numerical simulation, the proposed method of calculation, ideas, and the calculation results can be used as the reference for other similar projects.