Liu et al 2020b - Revision history

Rimni at 15:09, 14 December 2021

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‎2. Project Overview

Rimni at 13:48, 20 May 2021

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Liruifeng at 08:00, 3 March 2021

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Liruifeng at 06:50, 3 March 2021

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Liruifeng at 03:26, 8 February 2021

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Rimni at 10:05, 25 January 2021

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Rimni at 09:20, 25 January 2021

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Rimni at 09:20, 25 January 2021

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Rimni at 09:19, 25 January 2021

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 |}
-==Conclusion==
+==6. Conclusion==
 Based on a soft rock highway tunnel project in northwestern my country, this paper obtained the following conclusions by monitoring and analyzing the surrounding rock pressure and initial support stress at the site:

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 At present, many results have been achieved in monitoring measurement and analysis of the surrounding rock pressure and supporting force of soft rock tunnels. However, due to the heterogeneity and complexity of the geological environment of soft rock tunnels, it is still important to carry out systematic monitoring and measurement. The focus of the study, its support and control measures have not yet formed a complete system. According to the soft rock tunnel project of an expressway in Northwest China, the support invasion and distortion occurred during the construction process. Combined with the monitoring of surrounding rock deformation, steel arch stress, surrounding rock pressure and other monitoring of the tunnel, the surrounding rock deformation laws and stress characteristics of deep-buried soft rock tunnels are analyzed, and numerical simulations are carried out for different initial lining thicknesses and different initial elastic modulus. The comparison and analysis of the surrounding rock deformation control effect and surrounding rock pressure of different anchor rod lengths provide a design basis for tunnel construction and support.
-==2. Project Overview==
+==2. Project overview==
 This article relies on a project for a highway soft rock tunnel in northwestern China. It adopts a two-way separation design. The left line tunnel is 5779m long, the starting and ending pile numbers are ZK192+126～ZK197+905, the right line is 5798m long, and the starting and ending pile numbers are YK192+140～YK197+938, both of which are extra-long tunnels. The tunnel has an 811m long inclined shaft. During the construction of the tunnel,  the tunnel face collapse, initial support deformation, cracking, and limit invasion occurred during the construction process ([[#img-1|Figure 1]]). The left line pile number ZK197+036～ZK197+313 section has a total of 277m, and the right line pile number YK197+036～YK197+326 total 290m has been changed from the original design level VI surrounding rock to level V surrounding rock. Meters and the second liner in some areas cracked, which seriously delayed the progress of the project [14].

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 [6] Lunardi, P. Design and construction of tunnels: Analysis of controlled deformation in rocks and soils (ADECO). Springer, pp. XVII, 576 2008.
-[7]Sulem J., Panet M., Guenot A. Closure analysis and deep tunnels. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 24(3):145-154, 1987.
+[7] Sulem J., Panet M., Guenot A. Closure analysis and deep tunnels. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 24(3):145-154, 1987.
-[8]Pan Y.W., Dong J.J. Time-dependent tunnel convergence- I. Formulation of the model. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 28(6):469-475, 1991.
+[8] Pan Y.W., Dong J.J. Time-dependent tunnel convergence- I. Formulation of the model. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 28(6):469-475, 1991.
 [9] Sha P., Wu F., Li X., Liang N., Chang J. Compression deformation and supporting stress characteristics of surrounding rock in layered stratum tunnel under high ground stress conditions. Rock and Soil Mechanics, 36(05):1407-1414, 2015.
@@ Line 404: / Line 404: @@
 [10] Zhao Y., Liu J., Tian S. Experimental research on the mechanical characteristics of the soft surrounding rock support system of deep buried tunnels. Journal of Rock Mechanics and Engineering, 30(08):1663-1670, 2011.
-[11]Wu D. Calculation method and applicability of surrounding rock pressure of mountain tunnel. Beijing Jiaotong University, 2012.
+[11] Wu D. Calculation method and applicability of surrounding rock pressure of mountain tunnel. Beijing Jiaotong University, 2012.
 [12] Wang X., Wang Z., Zhang X., Zhao S., Liu D., Tong J. Research on calculation method of deformation pressure of surrounding rock of deep buried tunnel. Chinese Journal of Geotechnical Engineering, 1-10.

@@ Line 378: / Line 378: @@
 ==Acknowledgments==
-This study was supported by National Natural Science Fund Project (Grant No. 41877230), Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures (KF020-23), Fundamental Research Funds for the Central Universities CHD(Grant No. 300102281206).
+This study was supported by National Natural Science Fund Project (Grant No. 41877230), Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures (KF020-23),Open Fund of Xi’an Key Laboratory of Geotechnical and Underground Engineering（XKLGUEKF20-01），Fundamental Research Funds for the Central Universities CHD(Grant No. 300102281206).
 ==References==

@@ Line 378: / Line 378: @@
 ==Acknowledgments==
-This study was supported by National Natural Science Fund Project (Grant No. 41877230), Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures (KF020-23), Fundamental Research Funds for the Central Universities CHD.
+This study was supported by National Natural Science Fund Project (Grant No. 41877230), Open Fund of State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures (KF020-23), Fundamental Research Funds for the Central Universities CHD(Grant No. 300102281206).
 ==References==

@@ Line 382: / Line 382: @@
 ==References==
-[1] Ministry of Transportation. Statistical Bulletin of the Development of the Transportation Industry in 2018 [N]. China Communications News, 2019-04-12(002).
+<div class="auto" style="text-align: left;width: auto; margin-left: auto; margin-right: auto;font-size: 85%;">
-[2]''' Zhang Zhidao'''. Discussion and research on large deformation of squeezing surrounding rock tunnels [J]. Modern Tunnel Technology, 5-12+40,2003(02).
+[1] Ministry of Transportation. Statistical Bulletin of the Development of the Transportation Industry. China Communications News, 2019-04-12(002), 2018.
-[3]'''Li Guoliang, Zhu Yongquan.''' Wushaoling tunnel high ground stress weak surrounding rock large deformation control technology [J]. Railway Engineering Journal, 54-59,2008 (03).
+[2] Zhang Zhidao. Discussion and research on large deformation of squeezing surrounding rock tunnels. Modern Tunnel Technology, 5-12+40,2003(02).
-[4]''' Salamon M.D.G.''' Rock mechanics of underground excavations[C]. Proc, of the 3rd Congr, of the Inter, Soc, for Rock mech, 1974.
+[3]Li Guoliang, Zhu Yongquan. Wushaoling tunnel high ground stress weak surrounding rock large deformation control technology. Railway Engineering Journal, 54-59,2008(03).
-[5]''' Lunardi P.''' The design and construction of tunnels using the approach based on the analysis of controlled deformation in rocks [J]. Tunnels & Tunnelling International, 2000: 3-30.
+[4] Salamon M.D.G. Rock mechanics of underground excavations. In Advances in rock mechanics, Proceedings 3rd Congr Int Soc Rock Mech, Denver, vol 1B, pp 951–1099. Nat. Acad. Sci., Washington, DC.
-[6] '''Lunardi, Pietro'''. Design and construction of tunnels: analysis of controlled deformation in rocks and soils (ADECO[M]. Springer, 2008.
+[5] Lunardi P. The design and construction of tunnels using the approach based on the analysis of controlled deformation in rocks. Tunnels & Tunnelling International, pp. 3-30, 2000.
-[7]'''Sulem J,Panet M, Guenot A'''.Closure analysis, and deep tunnels[J].International Journal of RockMechanics&M Science in&Geomechanics Abstracts,24(3):145-154,1987.
+[6] Lunardi, P. Design and construction of tunnels: Analysis of controlled deformation in rocks and soils (ADECO). Springer, pp. XVII, 576 2008.
-[8]'''Pan Y W, DongJ J'''. Time -dependent tunnel convergence- -I. Formulation of the model[J]. InternationalJournal of Rock Mechanics & Mining Sciences, 1991, 28(6):469475.
+[7]Sulem J., Panet M., Guenot A. Closure analysis and deep tunnels. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 24(3):145-154, 1987.
-[9] '''Sha Peng, Wu Faquan, Li Xiang, Liang Ning, Chang Jinyuan'''. Compression deformation and supporting stress characteristics of surrounding rock in layered stratum tunnel under high ground stress conditions[J]. Rock and Soil Mechanics, 36(05) :1407-1414, 2015.
+[8]Pan Y.W., Dong J.J. Time-dependent tunnel convergence- I. Formulation of the model. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 28(6):469-475, 1991.
-[10] '''Zhao Yong, Liu Jianyou, Tian Siming'''. Experimental research on the mechanical characteristics of the soft surrounding rock support system of deep buried tunnels [J]. Journal of Rock Mechanics and Engineering, 30(08): 1663-1670, 2011.
+[9] Sha P., Wu F., Li X., Liang N., Chang J. Compression deformation and supporting stress characteristics of surrounding rock in layered stratum tunnel under high ground stress conditions. Rock and Soil Mechanics, 36(05):1407-1414, 2015.
-[11]'''Wu Dong'''. Calculation method and applicability of surrounding rock pressure of mountain tunnel[D]. Beijing Jiaotong University, 2012.
+[10] Zhao Y., Liu J., Tian S. Experimental research on the mechanical characteristics of the soft surrounding rock support system of deep buried tunnels. Journal of Rock Mechanics and Engineering, 30(08):1663-1670, 2011.
-[12] '''Wang Xiannian, Wang Zhilong, Zhang Xiao, Zhao Siguang, Liu Dagang, Tong Jianjun'''. Research on calculation method of deformation pressure of surrounding rock of deep buried tunnel [J]. Chinese Journal of Geotechnical Engineering: 1-10.
+[11]Wu D. Calculation method and applicability of surrounding rock pressure of mountain tunnel. Beijing Jiaotong University, 2012.
-[13] '''Tian Peng'''. Research on surrounding rock pressure and stress characteristics of secondary lining in high-ground stress soft rock tunnels[J]. Railway Standard Design, 60(08): 108-112, 2016.
+[12] Wang X., Wang Z., Zhang X., Zhao S., Liu D., Tong J. Research on calculation method of deformation pressure of surrounding rock of deep buried tunnel. Chinese Journal of Geotechnical Engineering, 1-10.
-[14] '''Wang Yingfan, Liu Qin, Hu Yongzhi, Liu Bingfei, Wei Lai.''' High deformation stress soft rock tunnel large deformation monitoring and support optimization [J]. Science and Technology and Engineering,,19(30):317-323,2019.
+[13] Tian P. Research on surrounding rock pressure and stress characteristics of secondary lining in high-ground stress soft rock tunnels. Railway Standard Design, 60(08):108-112, 2016.

@@ Line 368: / Line 368: @@
 # The situation is monitored from the site, and the method of first yielding and resisting can be adopted during construction, and the reserved deformation is appropriately increased to relieve the pressure of the initial support, and at the same time enhance the strength of the initial lining support. When the deformation rate of the surrounding rock slows down, the second lining shall be applied in advance.
 #Through numerical simulation of the actual project, when the thickness of the lining increases to 30cm, the displacement of the surrounding rock changes little. As the thickness of the lining continues to increase, the settlement of the surrounding rock vault has basically no change. The stress of surrounding rock by increasing the elastic modulus of support is lower than the pressure of surrounding rock when the thickness of the lining is increased, indicating that increasing the modulus of elasticity allows the stress of surrounding rock to be released, and at the same time it can exert a certain degree of self-supporting of surrounding rock. For the control of surrounding rock stress in deep-buried soft rock tunnels, increasing the elastic modulus is more effective than increasing the lining thickness. Increasing the length of the bolt does not have a significant effect on the control of the surrounding rock displacement. When the length of the bolt is in the range of 3~5m, the displacement of the surrounding rock decreases as the length of the bolt increases. When the length of the bolt is greater than 5m, the surrounding rock displacement decreases. The rock displacement decreases slowly, and the control of the bolt length on the surrounding rock displacement is obviously weakened.<br>
+'''Data Availability''': The Monitoring data used in this study were obtained from soft rock tunnel project of a Highway in Northwest China .The monitoring content includes Clearance convergence, vault settlement, surrounding rock pressure, spray concrete stress, steel frame stress. The monitoring instruments used include total station, pressure cell, concrete strain gauge and vibrating wire surface strain gauge.Data used to support the results of this study can be obtained from the corresponding author.
-'''Data Availability：'''The Monitoring data used in this study were obtained from soft rock tunnel project of a Highway in Northwest China .The monitoring content includes Clearance convergence, vault settlement, surrounding rock pressure, spray concrete stress, steel frame stress. The monitoring instruments used include total station, pressure cell, concrete strain gauge and vibrating wire surface strain gauge.Data used to support the results of this study can be obtained from the corresponding author.
 ==Conflicts of Interest ==

← Older revision		Revision as of 09:20, 25 January 2021
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	Based on a soft rock highway tunnel project in northwestern my country, this paper obtained the following conclusions by monitoring and analyzing the surrounding rock pressure and initial support stress at the site:		Based on a soft rock highway tunnel project in northwestern my country, this paper obtained the following conclusions by monitoring and analyzing the surrounding rock pressure and initial support stress at the site:
−	~~<ol>~~

	# When the three-step method is used for construction, the initial surrounding rock pressure increases rapidly, and the surrounding rock pressure increases slowly after the invert is constructed, and the surrounding rock pressure gradually stabilizes after the second lining is constructed. During the excavation stage of the upper step, the deformation of the surrounding rock increases sharply, and the deformation rate is large. The deformation rate of the surrounding rock during the middle step excavation is slowed down. At this stage, the surrounding rock deformation is mainly dominated by the excavation unloading effect, followed by extrusion deformation, which is the key to construction control.		# When the three-step method is used for construction, the initial surrounding rock pressure increases rapidly, and the surrounding rock pressure increases slowly after the invert is constructed, and the surrounding rock pressure gradually stabilizes after the second lining is constructed. During the excavation stage of the upper step, the deformation of the surrounding rock increases sharply, and the deformation rate is large. The deformation rate of the surrounding rock during the middle step excavation is slowed down. At this stage, the surrounding rock deformation is mainly dominated by the excavation unloading effect, followed by extrusion deformation, which is the key to construction control.