SMW双排桩基坑支护设计及应用

Design and Application of SMW Double-Row-Piles Foundation Pit Support

通过SMW双排桩基坑支护工程的应用实例,探讨了SMW双排桩支护的一些设计及应用时需考虑的问题。提出了在深厚软弱地层或深厚透水土层中基坑支护中可优先采用SMW双排桩支护型式,且双排桩前后桩顶宜采用水平刚度较大的盖板连接。同时提出SMW双排桩可按照抗弯刚度相等原则,采用等效混凝土桩径的方法进行设计。最后对深厚软弱地层或深厚透水土层采用SMW双排桩支护进行了应用分析,并提出软弱地层双排桩宜适当增加后排桩桩长提高支护整体稳定性,深厚透水土层中双排桩宜适当增加前排桩桩长提高支护抗倾覆稳定性。SMW双排桩基坑支护工程实例证明了该支护型式的位移控制效果很好,基坑顶水平位移只有0.8 mm。

Based on the application of SMW double-row-piles foundation pit support engineering,discussed some design and application problems of SMW double-row-piles support.It is suggested that SMW double-row-piles should be used in the foundation pit support in the deep and thick soil-foundation or the deep and thick permeable-foundation,and the cover plate with larger horizontal rigidity should be used to connect the front and rear pile tops of the double row piles.At the same time,the SMW double-row-piles can be designed by the method of equivalent concrete pile diameter according to the principle of equal bending rigidity.At last,the application of SMW double-row-piles in deep and thick soil-foundation or deep and thick permeable-foundation is analyzed,and it is suggested that the length of the rear row piles should be increased properly to improve the global stability of the support in the deep and thick soil-foundation,and the length of the front row piles should be increased properly to improve the anti-overturning stability of the support in the deep and thick permeable-foundation.The example of SMW double-row-piles foundation pit support project proves that the displacement control effect of the support is very good,and the horizontal displacement of the foundation pit top is only about 0.8 mm.