砂性土中鉆孔灌注樁施工質量控制要點

孫靜 李亞東

摘 要：鉆孔灌注樁是目前國內公路橋梁和房屋建筑等土木工程中應用最為廣泛的樁基基礎類型之一。鉆孔灌注樁不僅可有效解決抗震、承載等問題，還具備施工噪音小、擠土效應低等環境保護問題。隨著高層建筑的發展，建筑基礎和樁基深度顯著增加。灌注樁在進入砂性土層時，其成孔和成樁質量以及承載力都將受到砂的影響。本文則通過工程實踐所得，對砂性土中鉆孔灌注樁的施工難點進行了分析，著重指出了泥漿系統在保證成孔和成樁質量中的重要性，概要總結了相對應的控制措施，可為今后類似樁基基礎的施工和驗收提供借鑒。

關鍵詞：鉆孔灌注樁；砂性土層；泥漿系統

Sandy soil in bored pile construction quality control points

Sun Jing， Li Yadong

（ Shanghai branch of Engineering Consulting Company Limited， Shanghai 20000 China ）

Abstract： bored pile is the current domestic highway bridge and building construction and civil engineering of the most widely used type of pile foundation. Bored pile not only can effectively solve the problems such as earthquake， bearing， but also have low construction noise， low soil squeezing effect environmental protection problem. With the development of high-rise buildings， the building foundation and pile depth increased significantly. Bored pile in sandy soil， the hole and into a pile quality and capacity will be influenced by the effect of the sand. In this paper， through the engineering practice income， on sandy soil in the construction of bored pile difficulty undertook an analysis， pointed out emphatically the mud system to ensure the quality of pile hole and into the importance are summarized， the corresponding control measures， for similar pile foundation construction and acceptance to provide reference.

Key words： bored pile， sandy soil， mud system

引言

灌注樁是指通過機械鉆孔、鋼管擠土或人力挖掘等手段在地基土中形成樁孔，并在其內放置鋼筋籠、灌注混凝土而做成的樁。依照成孔方法不同，灌注樁可分為沉管灌注樁、鉆孔灌注樁和挖孔灌注樁等多種。其中，鉆孔灌注樁因其工藝特點，可不受樁徑和樁深的限制，適用于粘性土、粉土、砂土、填土、碎石類，以及地質條件比較復雜、夾層多和風化不均、軟硬變化較大的巖層，故廣泛應用于高層、超高層的建筑物和重型構筑物中。但由于地下施工的不可預計因素，加之鉆孔灌注樁的工序繁多，造成其質量離散性相對較大，容易出現塌孔、縮孔、孔斜、沉渣過大以及斷樁、夾泥等等質量問題，而這些問題之間往往存有很大的關聯性和系統性，成孔質量為首要關鍵。……