本文選題：超深防滲墻 + 接頭管法��； 參考：《天津大學》2014年博士論文

【摘要】：作為土石壩基礎(chǔ)工程中最重要的防滲設(shè)施之一，防滲墻對于保證大壩安全、減少庫區(qū)滲漏具有重要作用。近年來，隨著水利水電工程建設(shè)的不斷發(fā)展，水電開發(fā)逐漸向西部山區(qū)和高海拔地區(qū)推進，水利建設(shè)的迅速發(fā)展對超深覆蓋層地區(qū)的混凝土防滲墻技術(shù)提出了更高要求。 各單元墻段由接縫連接成防滲墻整體，墻段間的接縫是防滲墻的薄弱環(huán)節(jié)。在所有的墻段連接型式中，接頭管法由于接縫質(zhì)量好，且可避免混凝土浪費，加快施工進度而在超深防滲墻施工中深受青睞。理論分析和工程實踐表明，對于接頭管法的超深防滲墻施工而言，確定接頭管的拔管時機和拔管起拔力以及混凝土澆筑速度控制過程中的參數(shù)是制約施工質(zhì)量和施工進度的兩個關(guān)鍵問題。確定拔管時機主要包含兩個層面的意義：一是在澆筑混凝土后較早拔管，以避免由于混凝土凝固導致起拔困難，甚至引起鑄管；二是在澆筑混凝土后較晚拔管，以有充足的時間使混凝土穩(wěn)固，而不致由于外部荷載導致拔管后混凝土坍塌，實際上是相互矛盾而又緊密聯(lián)系的兩個方面；而拔管時機和孔斜對拔管力的大小具有重要影響。 論文以數(shù)值模擬為主要理論分析手段，以西藏旁多水利樞紐150m超深防滲墻施工為研究對象，對超深防滲墻混凝土澆筑進行了溫度～結(jié)構(gòu)場耦合分析，深入研究了超深防滲墻的拔管時機，對不同拔管時機、不同孔斜下的拔管力進行了分析，并以現(xiàn)場試驗進行了驗證；采用離散元法研究了混凝土澆筑過程中的施工控制參數(shù)，結(jié)果表明： （1）接頭管的拔管時機受控于混凝土的穩(wěn)固機制，受諸多因素影響，包括環(huán)境條件、荷載條件和施工條件等，具體到旁多項目150m的超深防滲墻而言，數(shù)值分析表明：在保持混凝土澆筑面距接頭管底端40m的情況下進行拔管是滿足要求的； （2）拔管力的大小主要與拔管時機和孔斜相關(guān)。不同的拔管時機導致接頭管與混凝土之間不同的接觸特性，進而影響拔管力；孔斜會增大拔管力，且隨著孔斜增加，拔管力增加迅速。在初澆混凝土40m拔管且無孔斜情況下，拔管力大小約為500t； （3）接頭管法施工混凝土澆筑參數(shù)控制主要包括澆筑導管口距槽孔底部最佳距離、導管在混凝土中的埋深、不同澆筑深度下澆筑混凝土下降速度等。數(shù)值分析表明：①混凝土初澆時，澆筑導管距槽底距離應控制在3～4倍導管直徑范圍；②澆筑結(jié)束階段，澆筑導管內(nèi)外混凝土高差應控制在5m以內(nèi)；③隨防滲墻深度的增加，混凝土在導管內(nèi)下降形態(tài)呈較明顯的間斷現(xiàn)象，但在150m的深度范圍內(nèi)無明顯離析和粗細骨料分離現(xiàn)象； （4）現(xiàn)場實踐表明，拔管時機以初澆混凝土后7～8小時為宜，即澆筑混凝土40m左右開始拔管；拔管力大小受諸多因素影響，主要與接頭管與混凝土之間的接觸特性和孔斜相關(guān)�，F(xiàn)場實踐與理論分析成果具有較好一致性。 論文給出了超深防滲墻接頭管法施工中拔管時機和拔管力的分析方法，同時，對混凝土澆筑過程中控制參數(shù)的選取進行了初步探討，對于提高超深防滲墻施工質(zhì)量和加快施工進度具有一定的參考價值。
[Abstract]:As one of the most important foundation of earth rockfill dam anti-seepage facilities, anti-seepage wall to ensure dam safety, which plays an important role in reducing the reservoir leakage. In recent years, with the continuous development of hydropower projects, hydropower development gradually advancing to the western mountains and high altitude, the rapid development of water conservancy construction of ultra deep covered concrete cutoff wall the region has put forward higher requirements.
Each cell wall section connected into impervious wall by the seam, the seam between the wall section is the weak link of impervious wall in wall section. All the connection type, joint tube method due to the joint quality is good, and can avoid the waste concrete, accelerate the construction progress in super deep diaphragm wall construction in theoretical analysis show that favored. And the engineering practice, for the joint tube method for super deep diaphragm wall construction, determine the extubation joint pipe pulling force and concrete pouring speed control process parameters are two key problems restricting the construction quality and the construction progress of the time and extubation. Determine the extubation time mainly includes two levels: one is after the pouring of concrete early extubation, in order to avoid the concrete solidification lead pulling difficult, even cause the pipes; two is in pouring concrete after late extubation, to have sufficient time to make the concrete solid, and not by The external load results in the collapse of concrete after extubation, which is actually contradictory and closely related to two aspects. The timing and the inclination of the pipe have an important influence on the size of the extubation force.
Based on the numerical simulation as the main means of theoretical analysis, taking Tibet Pangduo hydro 150m super deep diaphragm wall construction as the research object, the ultra deep cut-off wall concrete analyzed temperature field coupling to the structure, in-depth study of the super deep diaphragm wall on different extubation time, extubation time, different oblique hole the pulling force is analyzed, and based on the field test; study the construction parameters of the concrete pouring by discrete element method. The results show that:
(1) stable mechanism of tube extubation time is controlled by the concrete joints, affected by many factors, including environmental conditions, loading conditions and construction conditions, specific to the super deep diaphragm wall beside the 150m project, the numerical analysis shows that: in keeping concrete surfaces from the bottom joint pipe under the condition of 40m extubation is to meet the requirements of;
(2) the pulling force and extubation time and the size of the main hole. Different extubation time lead to different contact characteristics between the joint pipe and concrete, and then affect the pulling force; oblique hole will increase the pulling force, and with the increase of Kong Xie, the pulling force increases rapidly in the beginning of concrete 40m. Extubation and no hole case, the pulling force is about 500t;
(3) joint control parameters of concrete pouring construction method mainly includes pouring pipe mouth from the bottom slot optimal distance, catheter in concrete depth, different depth of concrete pouring down speed. Numerical analysis shows: the concrete initial pouring, pouring pipe from the tank bottom should be controlled at a distance of 3~4 times the diameter of the tube range the end of the stage; pouring, pouring pipe inside and outside the concrete height should be controlled within 5m; with the increase of the depth of the concrete cutoff wall, decreased in the duct shape is discontinuous phenomenon obviously, but in the depth range of 150m no obvious segregation and coarse aggregate segregation;
(4) the field practice shows the extubation time in 7~8 hours after the beginning of concrete pouring of concrete that is appropriate, started around 40m extubation; pulling force size is influenced by many factors, the main pipe and the contact characteristics between concrete and oblique holes associated with joint. The field practice and theoretical analysis results have good consistency.
This paper gives a super deep diaphragm wall pipe construction method in extubation method, tube time and pull at the same time, the selection of control parameters of concrete pouring process are discussed, which has a certain reference value for improving the construction quality of super deep diaphragm wall and accelerate the construction progress.

【學位授予單位】：天津大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：TV543.8

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