本文選題：濕噴混凝土 + 公路隧道　； 參考：《長安大學》2014年碩士論文

【摘要】：我國在公路隧道施工中廣泛的采用了新奧法（New Austria Tunneling Method，簡寫NATM），新奧法以噴射混凝土、錨桿加固和量測技術(shù)為三大支柱。長期以來，公路隧道施工中普遍采用干噴混凝土施工工藝，但是干噴混凝土由于施工工藝和施工設備等原因，混凝土配合比中的水由操作工人噴嘴處無計量方式的直接加入，粉態(tài)速凝劑也由操作工人無計量方式的添加，導致根本無法控制混凝土的水灰比和外加劑的實際參量，故強度根本無法保障；給公路隧道的初期支護質(zhì)量和施工過程及運營階段的安全造成了較為嚴重的影響。本文以長春至深圳高速公路承德至朝陽段長逢溝隧道初期支護濕噴混凝土施工實例為依托，對濕噴混凝土的配合比設計與優(yōu)化、抗壓強度參數(shù)、濕噴混凝土施工工藝及質(zhì)量管理進行了研究。內(nèi)容包括如下幾個方面： （1）根據(jù)《普通混凝土配合比設計規(guī)程》JGJ55-2000規(guī)定進行C25濕噴混凝土基準配合比設計（基準配合比為：mCo：mSo：mGo：mWo=430:899:766:205）；通過滿足施工工作性的需要，按照“不堵管、回彈少、附著性好”為原則進行現(xiàn)場實際濕噴試驗，對用水量、砂率、水泥用量等參數(shù)進行了調(diào)整和優(yōu)化，得出優(yōu)化配合比為mCo：mSo：mGo： mWo=424:902:769:205。 （2）通過施工現(xiàn)場采用濕噴工藝制作噴射混凝土大板試件，并按照相關(guān)噴射混凝土試驗檢測規(guī)程進行抗壓強度的測試。為了進行濕噴工藝與干噴工藝的混凝土強度對比分析，在上述濕噴施工現(xiàn)場，同時采用干噴工藝制作噴射混凝土大板試件，配合比參照濕噴配合比（除水用量）進行混合干料拌合并運輸至施工現(xiàn)場，按照相關(guān)試驗檢測規(guī)程進行混凝土強度的測試。通過對濕噴、干噴兩種施工工藝下，各50組試件的混凝土強度測試及數(shù)據(jù)分析可以得出，采用濕噴工藝施工的混凝土密實、飽滿，濕噴混凝土平均強度（30.44MPa）比干噴混凝土的平均強度（22.86MPa）高出7.58MPa，濕噴混凝土的標準方差、變異系數(shù)、平均極差及平均移動極等指標參數(shù)差明顯低于干噴混凝土，濕噴混凝土的強度指標質(zhì)量穩(wěn)定性明顯優(yōu)于干噴混凝土。 （3）通過長逢溝隧道噴射混凝土回彈率現(xiàn)場測定，得出邊墻平均回彈率9.1%，拱頂平均回彈率18.8%，，與相關(guān)文獻資料顯示的干噴混凝土回彈率邊墻部位為20～30%，拱頂部位為40～50％對比可以得出，濕噴混凝土的回彈率明顯低于干噴混凝土。 （4）噴射混凝土回彈率、密實度的影響因素主要有隧道圍巖狀態(tài)、混凝土配合比、施工方法（壓送壓力、噴射距離、噴射角度、噴射位置、噴射作業(yè)操作工人技術(shù)水平等）。噴射過程中，應根據(jù)出料情況調(diào)整風量，風壓控制在0.3~0.6MPa之間；嚴格控制噴槍與噴射面的距離和噴槍與噴射面的夾角，噴槍與噴射面的距離為1.0～1.5m，噴槍與噴射面基本保持垂直并連續(xù)平穩(wěn)地按小圓周形或橢圓形螺旋狀旋轉(zhuǎn)噴射，可以有效的降低回彈量，提高密實度。 （5）濕噴混凝土質(zhì)量控制中嚴格控制原材料質(zhì)量、加強施工作業(yè)管理、強化養(yǎng)護管理等是關(guān)鍵因素，針對強度、厚度、空洞、平整度、滲水等質(zhì)量通病應該采取有效措施辦法進行控制。
[Abstract]:In our country, are extensively used in highway tunnel construction of NATM (New Austria Tunneling Method, abbreviated NATM), the new Austrian method to shotcrete, anchor reinforcement and measurement technology for the three pillars. For a long time, the dry spraying concrete construction technology is widely used in highway tunnel construction, but the dry sprayed concrete due to the construction process and construction equipment Other reasons, concrete mix ratio in the water by directly adding workers without metering nozzle, add powder accelerator by workers without metering mode, resulting in the actual parameter cannot control the water cement ratio of concrete and admixture, the strength can not guarantee; for highway tunnel initial support quality and construction More serious impact caused by the process and operation stage. In this paper, the safety of wet shotcrete construction example Changchun Shenzhen Expressway to Chengde Chaoyang section of Changfeng tunnel initial support based on the mix design and optimization of wet sprayed concrete, compressive strength, wet shotcrete construction technology and quality management are studied. The contents are as follows:
(1) according to the provisions of design code for >JGJ55-2000 C25 than the wet sprayed concrete mix proportion design of ordinary concrete base (base mix ratio: mCo:mSo:mGo:mWo=430:899:766:205); by meeting the needs of the construction work, in accordance with the "no plugging, less resilience, good adhesion for the principle of actual wet spray test for Water, sand ratio, dosage of cement and other parameters are adjusted and optimized, the optimum mix ratio is mCo:mSo:mGo:mWo=424:902:769:205.
(2) the construction site by the wet spray process of spray concrete slab specimens, and in accordance with the relevant rules of concrete injection detection test compressive strength test. In order to carry out the wet spray process and concrete strength comparison of dry shotcrete analysis in the wet shotcrete construction site, and the production of dry shotcrete shotcrete slabs Specimen mix reference wet spray mix (except water) mixed with dry mix transportation to the construction site, the concrete strength test in accordance with the detection test standard. Based on the dry jet wet spray, two kinds of construction technology, concrete strength test and data analysis of the 50 groups of specimens can be obtained. The construction technology of wet spraying Concrete is dense, full, wet sprayed concrete average strength (30.44MPa) than the average strength of sprayed concrete (22.86MPa) is higher than 7.58MPa, standard deviation, coefficient of variation of wet shotcrete, average range and average moving pole parameters difference was significantly lower than that of dry sprayed concrete, the strength index of the quality stability of wet shotcrete is better than dry Sprayed concrete.
(3) through the long tunnel on injection rate was detected on the concrete rebound, the side wall of the average rebound rate was 9.1%, the average crown rebound rate 18.8%, and the related literature shows that dry shotcrete rebound rate of side wall is 20 ~ 30%, 40 ~ 50% vault comparison can be obtained, the rebound rate of shotcrete dry spray was significantly lower than that of concrete.
(4) the shotcrete rebound rate, factors affecting the density of the main tunnel surrounding rock, concrete mix ratio, construction method (pressurization pressure, jet distance, jet angle, jet position, injection technology level of operation workers). In the injection process, should be based on the material conditions to adjust the air volume, air pressure control in 0.3~0.6MPa between strict control; For spray and spray distance and the angle between the surface and spray gun, spray gun and the distance is 1 ~ 1.5m, spray gun and spray surface remained vertical and continuously and smoothly by small circular or oval shaped spiral jet, can effectively reduce the springback, improve the compactness.
(5) wet sprayed concrete quality control and strictly control the quality of raw materials, strengthen construction management, strengthen the maintenance and management are the key factors for the strength, thickness, hole, flatness, water quality defects should take effective measures to control.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：U455.48;U459.2

【參考文獻】

相關(guān)期刊論文 前10條

1 汪在芹;石妍;李家正;閆小虎;;噴射混凝土的室內(nèi)檢測方法及性能試驗研究[J];長江科學院院報;2012年03期

2 王小寶;濕式混凝土噴射機的類型及發(fā)展[J];工程機械;2000年02期

3 陳向陽;公路隧道濕噴混凝土施工技術(shù)與研究[J];公路交通科技;2003年01期

4 盧照輝;噴射混凝土配合比設計[J];混凝土;2002年10期

5 胡新民,李世秋,吳村,白瑛琦;淺談公路隧道圍巖支護濕噴鋼纖維混凝土施工技術(shù)[J];混凝土;2004年12期

6 肖軍;胡斌;葉偉;;濕噴混凝土配合比現(xiàn)場試驗分析[J];混凝土;2010年02期

7 仇益梅;;隧道工程噴射混凝土質(zhì)量控制與檢測[J];混凝土;2011年07期

8 張向東,張樹光,李永靖;噴射混凝土技術(shù)的發(fā)展與應用[J];煤;2001年01期

9 寧英武;;隧道工程噴射混凝土施工技術(shù)及質(zhì)量控制[J];交通世界(建養(yǎng).機械);2012年07期

10 付文鳳;;對隧道噴射混凝土幾種工藝的比較[J];科學之友;2012年12期

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