【摘要】：西部地區(qū)氣候條件嚴(yán)酷、水文地質(zhì)條件復(fù)雜，隧道襯砌混凝土易出現(xiàn)開裂、滲漏、凍融及侵蝕破壞等耐久性問題�；炷量�?jié)B性是混凝土耐久性的一個(gè)重要方面，因此本文從混凝土抗?jié)B性能方面出發(fā)，結(jié)合西部地區(qū)特定的氣候環(huán)境與水文地質(zhì)條件，提出滿足隧道二次襯砌各項(xiàng)性能要求的混凝土配合比設(shè)計(jì)思路，解決隧道襯砌結(jié)構(gòu)的滲漏問題。 通過對(duì)石灰石粉、粉煤灰單摻和二者復(fù)摻對(duì)水泥砂漿的基本性能影響研究，發(fā)現(xiàn)少量石灰石粉可提高水泥砂漿流動(dòng)性及早期強(qiáng)度，粉煤灰可提高水泥砂漿的流動(dòng)性、后期強(qiáng)度、能抑制收縮；兩者進(jìn)行合理的復(fù)摻可提高水泥砂漿的流動(dòng)性、降低收縮，雖然早期強(qiáng)度略有降低，但對(duì)后期強(qiáng)度有積極的影響。 通過對(duì)影響混凝土強(qiáng)度及抗?jié)B性能的各個(gè)因素研究，采用正交試驗(yàn)選定影響混凝土強(qiáng)度及抗?jié)B性能的主要四個(gè)因素進(jìn)行研究，結(jié)果表明：在選定的因素水平范圍水膠比是影響混凝土抗?jié)B性能最顯著的因素，粉煤灰摻量、石灰石粉摻量影響較小，而砂率對(duì)混凝土抗?jié)B性能影響不顯著。四個(gè)因素對(duì)混凝土抗?jié)B性能影響的程度是水膠比㧐石灰石粉摻量㧐粉煤灰摻量㧐砂率。根據(jù)隧道二襯混凝土的特點(diǎn)提出其配合比設(shè)計(jì)思路，采用低水膠比并加入大摻量的摻合料及高效減水劑來平衡混凝土強(qiáng)度、流動(dòng)性和抗?jié)B性三者的關(guān)系。通過試驗(yàn)對(duì)比優(yōu)選出兩組抗?jié)B性能優(yōu)異的混凝土，其水膠比分別為0.3、0.38，摻合料總量分別為50%、30%。再通過試驗(yàn)優(yōu)選出這兩組混凝土配合比的最佳用水量，比選出防滲性能良好的外加劑FSL，最終優(yōu)化出兩組符合隧道二次襯砌防滲混凝土配合比，對(duì)兩組配合比進(jìn)行抗?jié)B等級(jí)的試驗(yàn)，抗?jié)B等級(jí)均達(dá)到P12以上，為隧道二次襯砌混凝土配合比設(shè)計(jì)提供參考。 通過分析研究證明水膠比是影響混凝土抗?jié)B性能最重要的因素，水膠比越低抗?jié)B性能越好，，配制防滲混凝土?xí)r，在滿足工程其他性能的前提下建議選擇低水膠比；適量的粉煤灰和石灰石粉可以降低水泥基材料收縮，提高混凝土的抗?jié)B性能，應(yīng)用在隧道二次襯砌混凝土工程中可滿足施工性能及力學(xué)要求，一定程度上提高了隧道二次襯砌混凝土抗?jié)B問題，且粉煤灰和石灰石粉替代水泥可以降低工程成本，具有一定的經(jīng)濟(jì)效益。
[Abstract]:The climatic conditions in the western region are severe, the hydrogeological conditions are complex, and the tunnel lining concrete is prone to cracking, leakage, freezing and thawing, erosion and other durability problems. The impermeability of concrete is an important aspect of the durability of concrete. Therefore, this paper starts from the aspect of concrete impermeability and combines the specific climatic environment and hydrogeological conditions in the western region. In order to solve the leakage problem of tunnel lining structure, the design idea of concrete mix ratio which meets the performance requirements of secondary lining of tunnel is put forward. Through the study of the influence of lime powder, fly ash and both on the basic properties of cement mortar, it is found that a small amount of limestone powder can improve the fluidity and early strength of cement mortar, and fly ash can improve the fluidity of cement mortar and the later strength of cement mortar. It can inhibit contraction; It can improve the fluidity of cement mortar and decrease the shrinkage of cement mortar. Although the early strength decreases a little, it has a positive effect on the later strength of cement mortar. Through the study of the factors affecting the strength and impermeability of concrete, the main four factors which affect the strength and impermeability of concrete are selected by orthogonal test, and the main factors affecting the strength and impermeability of concrete are studied. The results show that the ratio of water to glue is the most significant factor affecting the impermeability of concrete in the range of the selected factors. The content of fly ash and limestone powder have little effect on the impermeability of concrete, while the sand ratio has no significant effect on the impermeability of concrete. The effect of the four factors on the impermeability of concrete is the ratio of water to binder? Lime powder? Fly ash content? Sand rate According to the characteristics of tunnel second lining concrete, the design idea of its mix ratio is put forward. The relationship among strength, fluidity and impermeability of concrete is balanced by using low water binder ratio, adding large amount of admixture and superplasticizer to balance the relationship among the strength, fluidity and impermeability of concrete. Two groups of concrete with excellent impermeability were selected by experiment. The ratio of water to binder was 0.3 and 0.38 respectively. The total amount of admixture was 50% and 30% respectively. Then the optimum water consumption of the two groups of concrete mix ratio was optimized through the test, and finally two groups of anti-seepage concrete mix ratio were optimized according to the secondary lining of tunnel by selecting the addition agent FSL, with good anti-seepage performance. The impermeability grade of the two groups is above P12, which provides a reference for the design of the mixture ratio of the secondary lining concrete in the tunnel. Through the analysis and research, it is proved that the water-binder ratio is the most important factor affecting the impermeability of concrete. The lower the water-binder ratio, the better the impermeability. In the preparation of anti-seepage concrete, it is suggested to choose the low water-binder ratio under the premise of satisfying the other properties of the project. Appropriate amount of fly ash and limestone powder can reduce the shrinkage of cement-based materials and improve the impermeability of concrete, which can meet the requirements of construction performance and mechanics in the secondary lining concrete engineering of tunnel. The impermeability problem of tunnel secondary lining concrete has been improved to a certain extent, and the replacement of fly ash and limestone powder for cement can reduce the engineering cost and has certain economic benefits.
【學(xué)位授予單位】：長(zhǎng)安大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：U454

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