旋挤钻法在软土及砂土地层施工灌注桩的研究
Study on Construction of Cast-in-place Pile in Soft Soil and Sandy Soil by Rotary Extrusion Drilling Method
朱正余 1陶涛 1陈珣 1王玉波 1顾乡 1常聚友 2侯龙3
作者信息
- 1. 中铁十局集团有限公司,济南 250000
- 2. 中铁二院工程集团有限责任公司,成都 610031
- 3. 中铁四局集团有限公司,合肥 230000
- 折叠
摘要
研究目的:采用常规旋挖钻法在地下水丰富的黏土地层和软土及砂土地层施工的灌注桩,部分灌注桩因坍孔出现扩径和缩径,扩径浪费混凝土,缩径使灌注桩不合格,由此提出把旋挖钻法改进为旋挤钻法,达到灌注桩轻微扩径不缩径不浪费混凝土的完整合格桩,本文对其展开研究.研究结论:(1)把旋挖钻法钻斗的慢速重钻改进为旋挤钻法钻斗的快速轻钻可行,可减小振动,挤密孔壁土,预防孔壁坍孔;(2)旋挤钻法成孔对于地表浅部极易坍孔地层用长护筒护壁,且护筒长度要大于极易坍孔地层厚度,对于易坍孔和不易坍孔地层用比重1.25和1.15等指标的泥浆护壁,且泥浆护壁是以垂直式的可控泥浆和离心力水平式的扰动土混合泥浆共同作用于护壁,迫使孔内部分扰动土与泥浆粘黏旋挤进入孔壁内,孔壁得到加固稳定不坍孔;(3)采用旋挤钻法在地下水丰富的黏土地层和软土及砂土地层施工的灌注桩,灌注混凝土充盈系数为1.02～1.03和1.04～1.05,均达到轻微扩径不缩径不浪费混凝土的完整合格桩;且成孔效率高,可减少污染、节约成本;(4)本研究成果可为铁路、公路等领域提高混凝土灌注桩施工质量提供参考.
Abstract
Research purposes:The conventional rotary drilling method in the ground water-rich clay stratum and soft soil and sandy soil stratum is used to construct cast-in-place piles,and some cast-in-place piles are enlarged and shrunk because of hole collapse,which wastes concrete and makes cast-in-place piles unqualified.This paper puts forward to improve the rotary drilling method to the rotary extrusion drilling method,so as to achieve the complete qualified pile with slight enlarging diameter and no reducing diameter and no wasting of concrete.Research conclusions:(1)It is feasible to improve the slow speed heavy drilling of the rotary drilling bucket into the quick light drilling of the rotary extruding drilling bucket to reduce the vibration and squeeze the soil of the hole wall to prevent the hole wall from collapsing.(2)The long casing wall is used to protect the shallow ground from collapse,and the length of the casing is greater than the thickness of the formation from collapse,for easy-to-collapse and difficult-to-collapse formation,mud wall protection with specific gravity of 1.25 and 1.15,and mud wall protection is the combination of vertical controllable mud and centrifugal horizontal disturbed soil mixed mud,the partially disturbed soil and mud are forced to stick and swirl into the hole wall,and the hole wall is strengthened and stabilized without collapsing.(3)The filling coefficient of cast-in-place concrete is 1.02～1.03 and 1.04～1.05 in the construction of cast-in-place pile in clay stratum,soft soil stratum and sand stratum with rich groundwater by rotary extrusion drilling method,all of the piles can be slightly enlarged without reducing the diameter without wasting the whole qualified concrete pile,and the hole-forming efficiency is high,the pollution is reduced,and the cost is saved.(4)The research results can provide reference for improving the construction quality of concrete cast-in-place pile in the fields of railway and highway.
关键词
旋挖钻法/旋挤钻法/慢速重钻/快速轻钻/护壁/质量Key words
rotary drilling method/rotary extrusion drilling method/slow speed heavy drilling/fast light drilling/wall protection/quality引用本文复制引用
出版年
2024
NETL
NSTL
万方数据