【摘要】：隨著全國公路隧道、城市地鐵及地下工程的迅速發(fā)展,噴射混凝土的用量呈急劇增長態(tài)勢,但目前噴射混凝土由于回彈率高,不僅造成巨大的材料浪費及施工效率低下,而且還對工程質(zhì)量及自然環(huán)境造成一定影響,因此研究低回彈噴射混凝土技術(shù)具有重要意義。本文在相關(guān)研究的基礎(chǔ)上,展開了對低回彈噴射混凝土技術(shù)以下幾個方面的研究。1、在噴射混凝土配合比設(shè)計時,通過引入超細(xì)礦物摻合料及回彈抑制材料改變混凝土的粘聚性及工作性,以期達(dá)到降低噴射混凝土回彈率。同時研究超細(xì)礦物摻合料復(fù)摻及回彈抑制材料對噴射混凝土評價指標(biāo)的影響,并利用水泥砂漿攪拌機測試各摻合料及回彈抑制材料對砂漿屈服應(yīng)力的影響。2、利用相機對噴嘴處混凝土料群進(jìn)行高速抓拍,研究噴射混凝土的射流特性、射流速度及擴散角度。針對噴射混凝土射流特性,建立回彈模型,研究并分析了噴射混凝土的回彈機理。3、通過室外噴射試驗,研究不同噴射工況下(噴射距離、工作壓力、噴射角度等)回彈率變化,得出了最佳的工作壓力、噴射距離和噴射角度。4、通過試驗分別驗證三種超細(xì)礦物摻合料復(fù)摻和兩種高分子回彈抑制材料對降低噴射混凝土回彈率的效果。上述研究成果可為隧道支護(hù)工程中噴射混凝土的配合比設(shè)計和作業(yè)方法提供理論依據(jù)。
[Abstract]:With the rapid development of national highway tunnel, urban subway and underground engineering, the amount of shotcrete is increasing rapidly. However, because of its high rebound rate, shotcrete not only causes huge waste of materials and low efficiency of construction, but also increases rapidly. It also affects the engineering quality and natural environment, so it is of great significance to study the technology of low rebound shotcrete. On the basis of relevant research, this paper studies the following aspects of low springback shotcrete technology. 1, in the design of mix ratio of shotcrete, The cohesion and workability of concrete were changed by introducing superfine mineral admixture and springback inhibiting material in order to reduce the rebound rate of shotcrete. At the same time, the influence of superfine mineral admixture and rebound inhibiting material on the evaluation index of shotcrete was studied. The effect of concrete mixture and springback inhibiting material on the yield stress of mortar was tested by cement mortar mixer. 2. The jet characteristics, jet velocity and diffusion angle of shotcrete were studied by using camera to capture the mass of concrete at the nozzle at high speed. According to the characteristics of jet, a springback model is established, and the springback mechanism of shotcrete is studied and analyzed. 3. Through outdoor spray test, the springback rate under different spray conditions (spray distance, working pressure, spray angle, etc.) is studied. The optimum working pressure, injection distance and spray angle were obtained. 4. The effects of three kinds of superfine mineral admixtures and two kinds of polymer rebound inhibiting materials on the springback rate of shotcrete were verified by experiments. The above research results can provide theoretical basis for the mix design and operation method of shotcrete in tunnel support engineering.
【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：U455.4

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