莫桑比克马普托大桥锚碇基础方案比选

摘要

The main bridge of Maputo Bridge in Mozambique is a suspension bridge with a sin‐gle span of 680 m .In order to make a rational anchor foundation scheme ,the types of caisson foundation and underground diaphragm wall were studied in accordance with the geological and hydrological condition at the bridge site and the load bearing characteristics of gravity anchor .I‐tems such as the selection of the base bearing stratum for the anchor foundation ,feasibility of the construction techniques and the applicability ,economic performance and rationality of the tech‐niques were also taken into account in the study .The results of the study indicate that the adapta‐tion of the underground diaphragm wall foundation is able to avoid the risks induced by variation of geological condition ,such as quicksand and heavy‐piping ,and is possible to strictly control the surrounding soil settlement during the construction process of anchor foundation and reduce the in‐fluence of the construction on the normal service of the surrounding railways to the maximum . When the form of the underground diaphragm wall foundation is determined ,in light of the prob‐lem of heavy‐piping ,the schemes of deep diaphragm wall and shallow diaphragm wall + curtain grouting+ waterhead lowering by deep well pumping and draining were studied .The results of the study demonstrate that by selecting the deep diaphragm wall ,the equipments required will be fe‐wer ,construction workmanship and procedure will be simplified ,the construction efficiency will be relatively higher ,and the construction duration will be shorter and controllable .As a result ,it is regarded as a rational anchor foundation scheme for Maputo Bridge .%莫桑比克马普托（M aputo ）大桥主桥为单跨680 m悬索桥，为确定马普托大桥锚碇基础方案，依据大桥桥位处的地质和水文情况，以及重力式锚碇的结构受力特点，针对锚碇基础基底持力层选择、施工工艺的适用性、技术可行性、经济性、合理性，分别对沉井基础和地下连续墙基础进行研究。研究结果表明：采用地下连续墙基础，施工期间可以避免由于地质情况变化带来的风险，如翻砂、突涌等；可以严格控制锚碇基础施工过程中对周围土体造成的沉降，最大限度地减少对周围铁路正常运营的影响。在确定地下连续墙基础形式后，针对施工过程中的突涌问题，对深地下连续墙和浅地下连续墙＋灌浆帷幕＋深井抽排水降低水头方案进行研究。研究结果表明：采用深地下连续墙基础，投入设备相对单一，施工工艺、工序简单，施工工效相对较高，施工工期较短，工期可控，应为马普托大桥合理的锚碇基础方案。