噴射灌漿引致之連續壁外擠變位

Outward Deformation of Diaphragm Wall Induced by Jet Grouting

謝旭昇(Hsii-Sheng Hsieh) ； 王崑瑞(Kun-Ruey Wang) ； 楊易璋(Yi-Chang Yang)

《地工技術》 93期 (2002/10) Pp. 33-42

https://doi.org/10.30140/SG.200210.0003

摘要

高壓灌漿工法常用於軟弱粘土之深開挖工程，其目的在於提高開挖區內土壤之強度，藉以提高開挖之穩定性及抑制壁體變位量。但高壓灌漿施作過程中常發現連續壁有外擠現象，其位移量可能高達十數公分，嚴重時甚至導致壁體破裂。基本上壁體外擠之主要原因並非灌漿所使用之壓力過大，而是因灌漿過程中無法順利迴漿排土，基地內土壤之體積因水泥漿之注入而持續增加，造成壁體受力向外推擠。本文以一實際施工案例說明高壓灌漿對連續壁之影響，文中除陳述現場觀測結果外，並以理論說明壁體外移之機制。

關鍵字

高壓灌漿 ； 壁體變位

並列摘要

Jet grouting is often used in deep excavation projects to improve the strength of soft ground. It not only increases the stability of excavation, but also limits the lateral displacement of retaining walls. However, it is often found that jet grouting may induce lateral outward displacement of diaphragm walls. The amount of displacement may exceed 10cm, leading to crack of diaphragm wall in extreme cases. Contrary to general belief, the outward movement of diaphragm wall is not induced by the seemingly high grouting pressure infact, difficulties in expelling waste disposal from the grout hole that leads to expansion of the soil mass is perhaps the governing mechanism. This paper presents to case of history a deep excavation. Both the construction characteristics of jet grouting as well as displacement patterns of diaphragm wall are addressed. The mechanism that leads to the outward movements of diaphragm wall is also delineated via a theoretical approach.

並列關鍵字

jet grouting ； diaphragm wall displacement