【摘要】：滬昆客專長(zhǎng)昆湖南段CKTJ-2標(biāo)一分部所屬工程位于石灰?guī)r巖溶強(qiáng)發(fā)育地區(qū),其橋梁基礎(chǔ)均采用深樁結(jié)構(gòu),巖溶強(qiáng)發(fā)育給施工帶來(lái)較大度的技術(shù)難度：最深的基樁達(dá)126m,最大的溶洞跨度達(dá)60m,穿越層數(shù)最多的串洞達(dá)10層,本文結(jié)合工程建設(shè)的需要和筆者的工作需要,從技術(shù)、質(zhì)量、經(jīng)濟(jì)、成樁效率等方面分析研究巖溶強(qiáng)發(fā)育地區(qū)深樁基礎(chǔ)施工技術(shù),總結(jié)施工經(jīng)驗(yàn)和注意事項(xiàng),主要工作和創(chuàng)新點(diǎn)有： 1.在巖溶強(qiáng)發(fā)育底層普遍、深樁大量采用的工程區(qū)域,針對(duì)僅依靠孔內(nèi)土自造泥漿的傳統(tǒng)工藝缺點(diǎn)：泥漿懸浮功能差、出渣困難、制約鉆進(jìn)效率、甚至不能起到良好的護(hù)壁作用；提出了采用膨潤(rùn)土、聚丙烯酰胺、纖維素等幾種材料造漿壁技術(shù),通過(guò)試驗(yàn)得出合理配合比。 2.一般情況下遇溶洞泥漿液面下降時(shí),一般采用通過(guò)片石加粘土填充溶洞,達(dá)到保證泥漿水頭的效果；但在遇到裂隙的情況下,特別是與裂隙連通的另一個(gè)溶洞較大的情況下,單純采用片石加黏土、或者水泥、甚至混凝土的措施都效果不佳,對(duì)此,本文提出了采用(粘土+麻繩)／(水泥+麻繩)再拋填的方法進(jìn)行堵漏。 3.針對(duì)背景工程巖溶強(qiáng)發(fā)育區(qū)地質(zhì)情況復(fù)雜多變,提出了對(duì)溶洞進(jìn)行預(yù)處理的方法,即分別采用注漿加固法(雙漿液)、壓漿法、灌砂法、超前鉆孔灌注混凝土法對(duì)溶洞進(jìn)行預(yù)處理,通過(guò)預(yù)處理大大降低了鉆孔過(guò)程中泥漿流失、塌孔等質(zhì)量問(wèn)題的發(fā)生頻率。 4.開(kāi)發(fā)專用鋼筋籠加工胎具及鋼筋籠下放吊具,用以減少鋼筋籠下放過(guò)程中對(duì)溶洞的擾動(dòng)和保證鋼筋籠的垂直度。 5.提出了在鋼筋籠上溶洞位置安裝100目的鐵紗網(wǎng)技術(shù),防止巖溶深樁混凝土灌注過(guò)程中混凝土擠塌溶洞壁。 本文提出的技術(shù)和方法可為同類工程借鑒。
[Abstract]:The project belonging to the first sub-division of CKTJ-2, which specializes in Hunan section of Hukunke, is located in the area where limestone karst is strong, and its bridge foundation adopts deep pile structure. The strong development of karst brings great technical difficulty to the construction: the deepest foundation pile is 126m, the largest karst cave span is 60m, the number of layers through the most serial holes is 10 stories. This paper combines the needs of the project construction and the author's work needs, from the technology, the quality, This paper analyzes and studies the construction technology of deep pile foundation in karst strong development area from the aspects of economy and pile forming efficiency, summarizes the construction experience and points for attention. The main work and innovations are as follows: 1. In the engineering area where deep piles are widely used in deep piles, the traditional technology shortcomings of mud self-made only by hole soil are: poor suspension function of mud, difficult slag production, restricted drilling efficiency, and even can not play a good role in wall protection; Bentonite, polyacrylamide, cellulose and other materials were used to make slurry wall technology, and the reasonable mix ratio was obtained by experiment. Generally speaking, when the slurry level of the cavern drops, the cavern is usually filled with flakes and clay to ensure the mud head, but in the case of a fissure, especially in the case of a larger cavern connected with the fissure, The simple use of flake stone with clay, cement, or even concrete is not effective. In this paper, the method of (clay hemp rope) / (cement hemp rope) is put forward to plug the leakage. 3. In view of the complex and changeable geological conditions of karst strong development area in background engineering, the pretreatment method of karst cave is put forward, that is, grouting reinforcement method (double grouting method), grouting method and sand pouring method, respectively. In this paper, the preprocessing of the cavern is carried out by the method of ahead drilling and pouring concrete, and the frequency of the quality problems such as mud loss and hole collapse in the drilling process is greatly reduced by the pretreatment. 4. In order to reduce the disturbance to the cavern and ensure the perpendicularity of the steel cage during the process of rebar cage dewatering, the special rebar cage processing placer and the rebar cage lower hanger are developed to ensure the perpendicularity of the reinforcement cage. In order to prevent concrete from collapsing into the wall of karst deep pile concrete during the pouring process, the technology of installing 100 purpose iron mesh in the position of karst cavern on the reinforcement cage is put forward in this paper. The techniques and methods presented in this paper can be used for reference by similar projects.
【學(xué)位授予單位】：中南大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U445.551

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