钉形水泥土双向搅拌桩基于扩大头高度的承载特性研究

针对钉形水泥土双向搅拌桩特殊的桩身结构，在试验桩体中心钻孔抽芯，埋入贴有应变片的塑料管，然后对桩体进行静载荷试验测定桩身应变，进而计算桩身轴力和附加应力，并分析探讨与扩大头高度相关的单桩承载特性。结果表明：桩身轴力和附加应力主要分布在扩大头高度范围内，且在桩身变截面处存在较大的轴力差和应力集中现象。最终得出扩大头高度在深厚软土中可取4～5m，最低不宜小于2m。

Study on bearing characteristic of T-shaped bidirectional soil-cement mixing pile based on expanding head height

Aiming at special structure of T-shaped bidirectional soil - cement deep mixing pile , drill and extract core samples in the test pile , then put the plastic pipe which affixed with strain gauges into the drill holes, based on static load test , the paper calculated the pile axial force of pile body and additional stress, and then analyzed the bearing features related to the expanding head height. Results show that the axial force of pile body and the additional stress are mainly distributed in the range of expanding head height, and there are a greater axial force difference and the phenomenon of stress concentration at the variable cross section of pile. It ultimately concluded that the most suitable height of enlarging head in deep soft soil is 4 -5 meters and the minimum height should not be less than 2 meters.