本文選題：盾構(gòu)隧道 + 上軟下硬地層��； 參考：《西南交通大學》2017年碩士論文

【摘要】：上軟下硬地層是盾構(gòu)隧道施工中經(jīng)常遇到的一種特殊地質(zhì)條件,由于開挖面地層特性的不均一性,在"軟硬不均地層"中盾構(gòu)掘進過程中,常常出現(xiàn)盾構(gòu)姿態(tài)不佳、管片局部應力集中甚至發(fā)生破損、地表沉降難以控制等諸多難題,使得施工質(zhì)量及工期等難以得到保障。探明盾構(gòu)在上軟下硬地層掘進過程中對周圍地層的擾動機理及管片襯砌結(jié)構(gòu)的受力特性,對于提升盾構(gòu)隧道在上軟下硬地層安全快速掘進具有重要意義。論文以深圳地鐵7號線西西區(qū)間盾構(gòu)隧道穿越上軟下硬地層為工程背景,綜合采用理論分析、離散元數(shù)值模擬等研究方法,從宏觀和細觀層面上對上軟下硬地層中盾構(gòu)掘進引起的地層擾動機理進行了系統(tǒng)分析,對上軟下硬地層盾構(gòu)施工中的地層改良進行了探討,并通過將不同掘進參數(shù)對地層擾動的影響與現(xiàn)場對掘進參數(shù)的統(tǒng)計數(shù)據(jù)相結(jié)合,開展了盾構(gòu)穿越上軟下硬地層掘進參數(shù)的優(yōu)化研究,得出以下主要成果:1、對上軟下硬地層中盾構(gòu)掘進對地層的擾動機理進行理論分析,采用三維顆粒流離散元數(shù)值模型模擬了上軟下硬地層中盾構(gòu)掘進所引起的擾動影響,在盾構(gòu)掘進引起地層擾動分區(qū)的基礎(chǔ)上,提出了上軟下硬地層中盾構(gòu)掘進引起的地層擾動分區(qū)。2、對巖性地層進行細觀參數(shù)標定,采用顆粒流離散元分析軟件PFC建立土壓平衡盾構(gòu)機(包括刀盤、刮刀、滾刀、土倉及盾殼等結(jié)構(gòu))—上軟(軟巖)下硬(硬巖)地層的三維離散元精細化模型,考慮滾刀破巖機理,提出了滾刀模型先隨刀盤平動和轉(zhuǎn)動微小時段再自轉(zhuǎn)相同步數(shù)的滾刀破巖離散化模擬方法。3、針對硬巖部分占掌子面25%、50%、75%等三種不同比例條件,在細觀層面上從地層中土體顆粒間接觸狀態(tài)、顆粒位移及地層應力的變化對上軟下硬地層中盾構(gòu)掘進引起的地層擾動進行了對比分析,探明了上軟下硬地層硬巖占比不同條件下盾構(gòu)掘進對周圍地層的擾動規(guī)律。4、采用三維數(shù)值模擬對不同地層條件及掘進參數(shù)下盾構(gòu)掘進引起地層擾動進行了對比分析,探明了加固軟弱地層對有效降低盾構(gòu)掘進對地層變形及管片內(nèi)力的影響,并結(jié)合掘進參數(shù)的現(xiàn)場統(tǒng)計數(shù)據(jù),給出了盾構(gòu)穿越上軟下硬地層時盾構(gòu)頂推力、掘進速度與刀盤轉(zhuǎn)速的參數(shù)優(yōu)化結(jié)果。
[Abstract]:Upper soft and lower hard stratum is a special geological condition often encountered in shield tunneling construction. Due to the heterogeneity of stratum characteristics of excavating surface, shield tunneling posture is often not good in the course of shield tunneling in "soft and hard uneven strata". The local stress concentration and even the damage of the segment, the surface subsidence is difficult to control and so on, which makes the construction quality and construction period difficult to be guaranteed. It is of great significance to prove the disturbance mechanism of shield tunneling to surrounding strata and the mechanical characteristics of segment lining structure in the driving process of upper soft and hard stratum, which is of great significance for the safe and rapid excavation of shield tunnel in upper soft and hard stratum. Based on the engineering background of the shield tunneling in the west section of Shenzhen Metro Line 7 through the upper soft and the lower hard strata, this paper synthetically adopts theoretical analysis, numerical simulation of discrete element and other research methods. In this paper, the mechanism of stratum disturbance caused by shield tunneling in upper soft and hard stratum is systematically analyzed from macro and micro level, and the formation improvement in shield construction of upper soft and hard stratum is discussed. By combining the influence of different tunneling parameters on formation disturbance and the statistical data of field tunneling parameters, the optimization of tunneling parameters of shield tunneling through upper soft and hard strata is studied. The following main achievements are obtained: 1. The disturbance mechanism of shield tunneling in upper soft and hard strata is theoretically analyzed, and the disturbance effect caused by shield tunneling in upper soft and hard stratum is simulated by using three dimensional particle flow discrete element numerical model. On the basis of the division of stratum disturbance caused by shield tunneling, the zone of stratum disturbance caused by shield tunneling in upper soft and hard stratum is put forward, and the meso-parameters of lithologic strata are calibrated. A three dimensional discrete element fine model of earth pressure balance shield machine (including cutter head, scraper, hob, earth bin and shield shell) under hard (hard rock) strata is established by using particle flow discrete element analysis software PFC. Considering the rock breaking mechanism of hob, a numerical simulation method of hob breaking rock discretization is put forward, in which the hob model firstly moves and rotates the same number of steps with the small time interval of the cutter head, and aiming at three different proportion conditions, such as the hard rock part occupies 2550% and 75% of the face of the palm. At the meso level, the disturbance caused by shield tunneling in upper soft and hard strata is compared and analyzed from the contact state of soil particles in stratum, the change of particle displacement and formation stress. The disturbance law of shield tunneling to surrounding strata under different conditions of hard rock ratio in upper soft and hard strata is proved. The three dimensional numerical simulation is used to compare and analyze the stratum disturbance caused by shield tunneling under different formation conditions and tunneling parameters. The effect of strengthening soft stratum on effectively reducing the deformation of stratum and the internal force of segment in shield tunneling is proved. Combined with the field statistical data of tunneling parameters, the top thrust of shield is given when the shield passes through the upper soft and lower hard stratum. Optimization results of the parameters of tunneling speed and cutter speed.
【學位授予單位】：西南交通大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U455.43

【參考文獻】

相關(guān)期刊論文 前10條

1 何祥凡;申興柱;王帆;姚佳兵;;盾構(gòu)隧道穿越上軟下硬地層施工力學特性分析[J];鐵道標準設計;2017年02期

2 白廷輝;劉樹佳;廖少明;;軟土地區(qū)盾構(gòu)掘進速度對地層擾動現(xiàn)場試驗研究[J];巖土力學;2016年07期

3 沈翔;袁大軍;;盾構(gòu)隧道掘進面穩(wěn)定性砂土模型試驗研究[J];土木工程學報;2015年S1期

4 何川;李訊;江英超;方勇;譚準;;黃土地層盾構(gòu)隧道施工的掘進試驗研究[J];巖石力學與工程學報;2013年09期

5 王巖;錢新;李e，

本文編號：1945071