Research on the Calculation of Tunnel Surrounding Rock Load in Sandy Cobble Soil Based on Barn Effect
WANG Mingsheng1, LU Junfu2, LI Minhao2, DENG Yonggang2
1. China Railway City Development and Investment Group Co. Ltd, Chengdu, Sichuan 610000, China; 2. State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu, Sichuan 610059, China
Abstract:Research purposes: The sandy cobble surrounding rock particle system has uneven gradation distribution and point-to-point contact between particles, which is easy to cause loose surrounding rock, instability collapse and other outstanding problems in tunnel construction process. According to the typical granular material characteristics of sandy cobble surrounding rock, based on the principle of granary effect, this paper uses the discrete element theory of granular material to explore the calculation method of surrounding rock load of sandy cobble tunnel. The meso-mechanical behavior of sandy cobble soil under different meso-structures is analyzed, and the influence of sandy cobble particle gradation on soil pressure is explored to reveal the influence law of tunnel span on tunnel surrounding rock load. Research conclusions:(1) A modified Janssen formula for calculating vertical pressure of sandy cobble soil is proposed, and the steering ratio of important coefficient in the formula is determined. (2) The influence law of sandy cobble particle gradation on vertical pressure and lateral pressure of soil is revealed, and the calculation formulas of bottom pressure and lateral pressure of sandy cobble soil are obtained. (3) Through the simulation experiment of different span tunnel model, the vertical load correction coefficient is proposed. The load calculation value of sandy cobble surrounding rock by using the correction coefficient method is similar to the simulation calculation results, which verifies the accuracy of the formula calculation. (4) The load calculation method of sandy cobble surrounding rock based on Janssen model is established, which can provide theoretical basis for fine design of tunnel in sandy cobble stratum.
王明胜, 路军富, 李旻昊, 邓永刚. 基于谷仓效应的砂卵石隧道围岩荷载计算研究[J]. 铁道工程学报, 2023, 40(1): 62-67.
WANG Mingsheng, LU Junfu, LI Minhao, DENG Yonggang. Research on the Calculation of Tunnel Surrounding Rock Load in Sandy Cobble Soil Based on Barn Effect. Journal of Railway Engineering Society, 2023, 40(1): 62-67.
孙文昊.土质地层中盾构隧道垂直荷载计算方法探讨[J].铁道工程学报,2009(10):69-73.Sun Wenhao. Research on the Calculation Method for Vertical Earth Pressure of Shield Tunneling Soil Layer [J]. Journal of Railway Engineering Society, 2009(10):69-73.
[2]
王浩,畅翔宇,张一鸣,等.高速铁路隧道围岩力学参数反演研究[J].铁道工程学报,2020(9):47-53. Wang Hao, Chang Xiangyu, Zhang Yiming,etc. Inversion Analysis of Mechanical Parameters of Surrounding Rock in High-speed Railway Tunnel[J]. Journal of Railway Engineering Society,2020(9):47-53.
[3]
Li P F, Wang F, Fang Q. Undrained Analysis of Ground Reaction Curves for Deep Tunnels in Saturated Ground Considering the Effect of Ground Reinforcement[J]. Tunnelling and Underground Space Technology, 2018(71):579-590.
[4]
宋伟涛,张佩,杜修力.含石量对砂卵石地层隧道开挖地表沉降影响研究[J].地下空间与工程学报,2021(S1):359-366.Song Weitao,Zhang Pei,Du Xiuli. Research on the Influence of Stone Content on Surface Settlement Caused by Tunnel Excavation in Sandy Cobble Stratum[J]. Chinese Journal of Underground Space and Engineering,2021(S1): 359-366.
[5]
Liang X, Ye F, Ouyang A H, etc. Theoretical Analyses of the Stability of Excavation Face of Shield Tunnel in Lanzhou Metro Crossing beneath the Yellow River[J]. International Journal of Geomechanics,2020(20):1-14.
[6]
田世雄,路军富,连鹏,等.粗粒含量对砂卵石土宏细观力学特性影响分析[J].科学技术与工程,2019(2):186-191.Tian Shixiong,Lu Junfu,Lian Peng,etc. Influence Analysis of Coarse Grain Content on Macro-mechanical Properties of Sandy Pebbles[J].Science Technology and Engineering,2019(2):186-191.
[7]
Abdel-Sayed G, Monasa F, Siddall W. Cold-formed Steel Farm Structures, Part 1: Grain Bins[J]. Structure Engineering,1985(10):2065-2089.
[8]
王立川. 浅埋偏压隧道围岩压力与开挖进尺优化的极限分析方法[D]. 长沙:中南大学, 2011.Wang Lichuan. Limit Analysis Method for Surrounding Rock Pressure and Excavation Footage Optimization of Unsymmetrical Pressure and Shallow Tunnel[D]. Changsha:Central South University, 2011.