某填海区深基坑支护椭圆环支撑受力变形分析

Stress Analysis of Elliptical Ring Supporting Structure in the Deep Excavation in the Nearshore Reclaimed Area

椭圆形内支撑环梁以受压为主,可以充分发挥混凝土抗压强度高的材料特性,但在实际工程应用中,不均匀荷载下椭圆形支撑容易产生较大弯矩和变形,存在严格的使用限制条件,在填海区复杂地质条件下超过20 m深基坑的应用案例很少。结合深圳填海区27.0 m深基坑椭圆形内支撑工程实例,建立了三维数值分析模型,模拟不同长短轴比的椭圆环支撑支护方案,分析椭圆形内支撑结构中围护结构和支撑环梁受力变形特性。结果表明,在不均匀荷载条件下,随着长短轴差值的不断增加,围护体和支撑环梁受力变形有较大变化甚至存在突变,而短轴增加对撑,可有效降低弯矩和变形。

The elliptical internal supporting structure is a typical compressive element and the material properties of reinforced concrete can be fully utilized.However,under the uneven loading conditions,large bending moments and excessive deformation might be generated so that the application of this supporting type has many limitations.Currently,the elliptical supporting structure is rarely used in deep excavations with depth greater than 20 meters in nearshore reclaimed areas.This paper presents the application of reinforced concrete elliptical structure as the supporting structure for a 27 meters deep excavation in the reclaimed area.The three-dimensional numerical analysis was used to simulate the performance of elliptical supporting structure with various aspect ratio.The deformation and stress conditions in the internal supporting structures are also investigated.The results indicate that,under the uneven loading conditions,with the increase of aspect ratio,large deformation and stress are observed in the supporting structure.Increase the cross strut supporting in the short direction can effectively reduce the deformation and bending moment.