【摘要】：隨著我國交通行業(yè)的快速發(fā)展,全國興起了隧道建設(shè)的高潮,越來越多的大斷面隧道相繼涌現(xiàn),加之全國各地的地鐵輕軌建設(shè)也陸續(xù)上馬,這些分布在城市中心的大斷面隧道對于隧道施工過程中的圍巖穩(wěn)定和爆破振動提出了更高的要求。超前導(dǎo)坑再擴挖工法能夠減少對未開挖圍巖的擾動,維持圍巖的穩(wěn)定。同時超前導(dǎo)坑再擴挖工法以其在爆破減震方面的獨特優(yōu)勢,日益被人們認(rèn)識和接受。另外超前導(dǎo)坑再擴挖工法可以利用TBM機開挖先行導(dǎo)坑,再用鉆爆法擴大至設(shè)計斷面。由于TBM機的直徑不依賴于隧道設(shè)計斷面,所以可以比較好的解決TBM機的循環(huán)使用問題。由于對超前導(dǎo)坑再擴挖工法的研究還比較少,所以本文對于這種工法進行了研究,主要研究內(nèi)容和研究成果如下:①詳細介紹了超前導(dǎo)坑再擴挖工法國內(nèi)外研究的現(xiàn)狀和目前存在的問題,從而確定了本文研究的方向。②對超前導(dǎo)坑法的施工流程、優(yōu)缺點以及施工過程中應(yīng)該注意的事項進行了簡要的闡述,然后從適用條件、工期、造價等方面將超前導(dǎo)坑再擴挖工法與其他施工方法進行對比,對超前導(dǎo)坑再擴挖工法特點進行了進一步闡述。③對于導(dǎo)坑開挖完成之后主隧道的擴挖問題,本文中提出了三種施工方案,并就四級和五級圍巖條件下應(yīng)用ANSYS程序?qū)θN擴挖方案進行了模擬分析。對各工況隧道關(guān)鍵點的變形和應(yīng)力進行了對比分析,提出了三種擴挖方案分別適用的圍巖地質(zhì)條件。④從理論和對試驗數(shù)據(jù)的分析論證了導(dǎo)坑的作用:導(dǎo)坑為爆破作業(yè)提供了臨空面,可以減小對未開挖巖體的擾動,起到減震的作用,同時可以減少隧道的炸藥使用量。⑤與全斷面爆破開挖相對比,利用ANSYS/LS-DYNA軟件分別就超前導(dǎo)坑再擴挖工法炸藥量降低10%、20%和30%三種情況研究了炸藥量降低值與振動速度的關(guān)系,從而對工程實踐提供理論指導(dǎo)。⑥針對某超前導(dǎo)坑法施作的隧道工程實例進行了數(shù)值模擬。
[Abstract]:With the rapid development of the transportation industry in China, the high tide of tunnel construction has sprung up throughout the country, and more large cross-section tunnels have emerged one after another. In addition, subway light rail construction in various parts of the country has also been launched one after another. These large section tunnels distributed in the center of the city put forward higher requirements for the stability of surrounding rock and blasting vibration in the course of tunnel construction. This method can reduce the disturbance to the unexcavated surrounding rock and maintain the stability of the surrounding rock. At the same time, it has been recognized and accepted by people day by day because of its unique advantage in blasting vibration reduction. In addition, the TBM machine can be used to excavate the pilot pit and then the drilling and blasting method can be extended to the design section. Because the diameter of TBM machine does not depend on the tunnel design section, it can solve the recycling problem of TBM machine. Because there is little research on the method of reexpanding and digging in advance guide pit, this paper has carried on the research to this kind of construction method. The main research contents and achievements are as follows: (1) the present situation and existing problems of the research on the method of leading-way pit re-expansion are introduced in detail, thus the research direction of this paper is determined. (2) the construction process of the lead-through pit method is introduced in detail. The advantages and disadvantages as well as the matters needing attention in the construction process are briefly expounded, and then the construction method of leading guide pit and other construction methods are compared with other construction methods from the aspects of applicable conditions, time limit, cost and so on. In this paper, three construction schemes are put forward for the expansion and excavation of the main tunnel after the completion of the excavation of the guide pit, and the characteristics of the reexpanding excavation method of the leading pit are further expounded in this paper. Three kinds of expansion and excavation schemes are simulated and analyzed by ANSYS program under the conditions of grade 4 and grade 5 surrounding rock. The deformation and stress of key points in tunnel under various working conditions are compared and analyzed. In this paper, three kinds of expansion and excavation schemes are put forward, which are applicable to the geological conditions of surrounding rock. 4. From the analysis of theoretical and experimental data, the function of the pilot pit is demonstrated: the pilot pit provides an empty surface for blasting operation, which can reduce the disturbance to the unexcavated rock mass. At the same time, it can reduce the use of explosives in the tunnel. 5 compared with the full-section blasting excavation, ANSYS/LS-DYNA software is used to reduce the explosive amount by 10% in the lead-through pit re-expansion excavation method, and the explosive amount of the tunnel is reduced by 10% in comparison with the full section blasting excavation. The relationship between the reduction value of explosive charge and vibration velocity is studied in three cases, 20% and 30%, thus providing theoretical guidance for engineering practice. 6 numerical simulation is carried out for a tunnel engineering example constructed by a preemptive tunnel pilot method.
【學(xué)位授予單位】：重慶交通大學(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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