摘要
为建设好一带一路沿线项目,以坦桑尼亚著名石头城姆万扎省的马古富力大桥为工程背景,针对其位于东非大裂谷维多利亚湖区,湖水为当地居民饮用水源,环保要求高;所处地层中夹有大量孤石、斜岩,桩基花岗岩最大强度达150 MPa,施工难度大;加之受限于交通路况条件,大型钻孔设备无法运输到现场,当地人员技术水平低,这都增加了该桥嵌岩桩的成孔难度。为此,通过对履带式回转钻孔、冲击钻孔、旋挖钻孔等进行方案比选、现场试验、质量检测、环保评价、经济分析,最终选择了旋挖钻+冲击钻接力成孔的施工方案;详述了施工流程、质量控制要点、人机料等资源组织、环水保施工措施;提出了斜岩、孤石、硬岩夹流沙层等特殊地质成孔,以及施工中遇到斜孔、卡钻、地层岩性误判等问题的应对措施;并对硬岩层冲击钻头消耗过大及钻头掉齿断裂等难题,研发了新型冲击钻钻头(获专利)。实践表明:东非维多利亚湖区嵌岩桩采用旋挖钻+冲击钻接力成孔是成功的,实现了安全质量及经济环保等目标,可为类似工程提供参考。
To build the projects along the Belt and Road,the Magufuli Bridge in Mwanza Province,a famous stone city in Tanzania,is taken as the engineering background.As it is located in the Lake Victoria area of the East African Great Rift Valley,the lake water is the drinking water source for residents,which makes high environmental protection requirements necessary.There are a large number of solitary stones and inclined rocks in the strata where the pile foundation granite has a maximum strength of 150 MPa,making construction difficult.In addition,due to the limited traffic conditions,large-scale drilling equipment cannot be transported to the site efficiently,with the low technical level of local personnel,it increases the difficulty of drilling work of the bridge rock socketed piles.Therefore,through scheme comparison,on-site testing,quality inspection,environmental protection evaluation,and economic analysis of tracked rotary drilling,impact drilling,and rotary drilling,the construction method of rotary drilling+impact drill relay drilling was ultimately selected;an elaboration was made on the construction process,key points of quality control,resource organization such as human-machine materials,environmental and water conservation construction measures,etc;it is proposed that special geological drilling methods such as inclined rock,solitary rock,and hard rock with flowing sand layers,as well as measures to address issues such as inclined holes,stuck drilling,and misjudgment of formation lithology encountered during construction;we also developed a new type of impact drill bit(patented)to address issues such as excessive consumption and breakage of hard rock impact drill bits.The practice has shown that the construction method of rotary drilling+impact drill relay drilling to form holes for socketed piles in the Lake Victoria area of East Africa has been successful,achieving safety,quality,economic,and environmental protection goals,and will provide a reference for similarly related projects.
作者
张军乐
ZHANG Junle(China Civil Engineering Construction Corporation,Beijing 100038,China)
出处
《铁道建筑技术》
2023年第7期124-128,共5页
Railway Construction Technology
基金
中国铁建股份有限公司科技研发计划项目(2022-C01)。
关键词
维多利亚湖
东非
嵌岩桩
成孔技术
环水保
Lake Victoria
East Africa
socketed pile
pile technology
environment and water protection
