深基槽重力式码头地基应力分布研究及基槽开挖优化

Foundation stress distribution regularity and trench optimization of gravity quay with deep foundation trench

对于基槽较深的重力式码头,若按照《重力式码头设计与施工规范》进行基槽底宽设计,基槽开挖量和回填量较大。为此文章通过有限元计算,探讨了在不同深度、不同基槽外侧土体弹模和下卧层土体弹模、以及不同基顶应力和后方边载情况下的地基应力分布规律,发现在较深处,后趾处的地基竖向附加应力可能比前趾处大,上述规范可能会高估地基应力扩散范围及低估地基应力值。之后基于Boussinesq理论解,给出相应荷载和基槽深度下地基应力扩散角的计算表,可以据此对基槽的底宽进行优化,并提出一种采用4个控制点的地基应力简化计算方法。进一步提出不按应力扩散范围确定基槽底宽的优化设计方法,并指出两点注意点,一是底宽范围内可能会发生应力集中现象,二是基槽外两侧土体的承载力需要进行验算。

As for the gravity quay with deep foundation trench,the excavated and backfilling volume of foundation trench will be very large according to design and construction code for gravity quay. Foundation stress regularities of the corresponding depth,young＇ s modulus of the soil outside and under the trench,base load and rear uniform load were concluded through the finite element calculation. It is found that at a deep place,the vertical additional stress of the foundation at the rear toe may be larger than that at the front,and the normative method may overestimate the stress diffusion range and underestimate the foundation stress value. Based on the Boussinesq solution,a table of the foundation stress diffusion angle under corresponding load and trench depth was proposed,with which the trench width at the bottom could be optimized. Besides,a simplified method for calculating the foundation stress with four control points was brought forward. Further more,an optimization method was proposed,in which the trench bottom width was not excavated according to the foundation stress distribution range. However,the bearing capacity of the stratum outside the trench needs to be checked and the stress concentration within the scope of the base width should not be ignored.