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Coal Geology & Exploration

The stability of long trench section in sand cobble stratum of mine water cutoff curtain

Abstract

Long-term high flow rate drainage of precipitation in open-pit coal mines has led to serious waste of groundwater resources in the mine area, rapid degradation of the ecological environment around the mine field, and significant increase in production and operation costs. The curtain interception and emission reduction technology provides a new water control idea for the water control in open-pit mines. The stability of the trench section is directly related to the safety and efficiency of the water cutoff curtain during construction, at the same time, it also has a great influence on the anti-seepage effect. Taking an open-pit coal mine in the eastern Inner Mongolia of China as an example, we used the two-dimensional and three-dimensional horizontal slice method to study the factors and laws affecting the stability of the long trench section, in order to explore the stability of the trench section in sandy cobble stratum during construction. The differences between the two-dimensional and three-dimensional horizontal slice methods in the calculation of safety coefficient were compared and analyzed. The stability of the trench section was simulated and analyzed with the help of FLAC3D software for two lengths of 17.5 and 22.5 m for the sand cobble stratum respectively. Combined with the above analysis results, the stability control measures of the long trench section of sand cobble stratum were derived and verified by ultrasonic testing. The results of the study show that the main factors affecting the stability of the trench section are: the nature of the formation geotechnical body, the excavation depth of the trench section, the mud level, the mud density, the difference between the mud level and the groundwater level and the length of the single width trench section. The stability of the long trench section can be increased by adjusting the mud parameters, increasing the mud level, lowering the groundwater level, optimizing the trenching sequence and controlling the trenching time. If the length of a single trench section does not exceed 21 m, the trench can be kept upright and stable, and the long trench technique is feasible.

Keywords

open-pit coal mine, water cutoff curtain, long trench section, stability, numerical simulation, horizontal slice method, sand cobble stratum

DOI

10.12363/issn.1001-1986.21.12.0794

Reference

[1] 曹海东,苗贺朝,迟赞,等. 基于低强度抗渗混凝土的露天煤矿帷幕截水技术[J]. 煤田地质与勘探,2020,48(4):61−67. CAO Haidong,MIAO Hechao,CHI Zan,et al. Water cutoff curtain technology of open–pit coal mine based on low strength impermeable concrete[J]. Coal Geology & Exploration,2020,48(4):61−67.

[2] 张雁. 露天煤矿防渗墙截渗减排机制及工程应用研究[D]. 北京：煤炭科学研究总院，2018.

ZHANG Yan. Study on the mechanism and engineering application of seepage cutoff and drainage reduction of diaphragm wall in open–pit coal mine[D]. Beijing：China Coal Research Institute，2018.

[3] 董书宁,王海,黄选明,等. 基于保障生态地下水位的露天煤矿主动保水技术研究[J]. 煤炭科学技术,2021,49(4):49−57. DONG Shuning,WANG Hai,HUANG Xuanming,et al. Research on active water conservation technology in open–pit coal mine based on ecological protection groundwater level[J]. Coal Science and Technology,2021,49(4):49−57.

[4] 张雁,田增林,曹海东,等. MJS工法在砾石层中的应用及成桩差异性[J]. 煤田地质与勘探,2020,48(2):147−151. ZHANG Yan,TIAN Zenglin,CAO Haidong,et al. Application of MJS construction method in gravel layer and pile forming difference[J]. Coal Geology & Exploration,2020,48(2):147−151.

[5] 彭巍,王海,王仲全,等. 深厚砂卵石层低温动水条件下咬合桩帷幕材料研发[J]. 煤田地质与勘探,2020,48(4):80−86. PENG Wei,WANG Hai,WANG Zhongquan,et al. Properties of the occluded pile curtain material under low temperature and dynamic water condition in deep and thick gravel layer[J]. Coal Geology & Exploration,2020,48(4):80−86.

[6] 王海,彭巍,曹海东,等. 露天煤矿截水帷幕效果检验方法及截水效果分析[J]. 煤田地质与勘探,2020,48(4):87−93. WANG Hai,PENG Wei,CAO Haidong,et al. Inspection method and analysis of the effect of water cutoff curtain in open–pit coal mine[J]. Coal Geology & Exploration,2020,48(4):87−93.

[7] 丁勇春,李光辉,程泽坤,等. 地下连续墙成槽施工槽壁稳定机制分析[J]. 岩石力学与工程学报,2013,32(增刊1):2704−2709. DING Yongchun,LI Guanghui,CHENG Zekun,et al. Analysis of trench face stability of diaphragm wall panel during slurry trenching[J]. Chinese Journal of Rock Mechanics and Engineering,2013,32(Sup.1):2704−2709.

[8] 黄选明,张雁,李文嵩,等. 我国露天煤矿水害特征与防治水技术[J]. 煤田地质与勘探,2020,48(4):53−60. HUANG Xuanming,ZHANG Yan,LI Wensong,et al. Summary of water disaster characteristics and water prevention and control technology in open–pit coal mines in China[J]. Coal Geology & Exploration,2020,48(4):53−60.

[9] 张厚美,夏明耀. 地下连续墙泥浆槽壁稳定的三维分析[J]. 土木工程学报,2000,33(1):73−76. ZHANG Houmei,XIA Mingyao. 3–D stability analysis of slurry trenches[J]. China Civil Engineering Journal,2000,33(1):73−76.

[10] 缪圆冰,江松,黄明,等. 基于强度折减的泥浆护壁槽局部稳定性计算及影响因素[J]. 工程地质学报,2018,26(4):874−881. MIAO Yuanbing,JIANG Song,HUANG Ming,et al. Local stability calculation and factors of slurry trench with strength reduction method[J]. Journal of Engineering Geology,2018,26(4):874−881.

[11] 路乾,胡长明,王晓华,等. 地下连续墙成槽施工槽壁整体稳定性分析[J]. 地下空间与工程学报,2021,17(3):864−871. LU Qian,HU Changming,WANG Xiaohua,et al. Analysis on the overall stability of trenching construction of diaphragm wall[J]. Chinese Journal of Underground Space and Engineering,2021,17(3):864−871.

[12] 丁勇春,程泽坤,王建华,等. 地下连续墙施工力学性状数值分析[J]. 岩土工程学报,2012,34(增刊1):87−92. DING Yongchun,CHENG Zekun,WANG Jianhua,et al. Numerical simulation of mechanical behavior of diaphragm wall during construction[J]. Chinese Journal of Geotechnical Engineering,2012,34(Sup.1):87−92.

[13] 夏元友,裴尧尧,王震,等. 地下连续墙施工影响应力重分布的数值模拟[J]. 岩土力学,2012,33(11):3433−3438. XIA Yuanyou,PEI Yaoyao,WANG Zhen,et al. Numerical simulation of stress redistribution during diaphragm wall construction[J]. Rock and Soil Mechanics,2012,33(11):3433−3438.

[14] ZHUO Hongchun,YANG Yuyou,ZHANG Zixin,et al. Stability of long trench in soft soils by bentonite–water slurry[J]. Journal of Central South University,2014,21(9):3674−3681.

[15] 邱明明,杨果林,申权,等. 深厚砂层地下连续墙槽壁稳定性特征及影响因素研究[J]. 铁道科学与工程学报,2020,17(5):1129−1139. QIU Mingming,YANG Guolin,SHEN Quan,et al. Study on characteristics and influence factors of slurry trench stability of diaphragm wall in deep sandy stratum[J]. Journal of Railway Science and Engineering,2020,17(5):1129−1139.

[16] 夏元友,裴尧尧,王智德,等. 地下连续墙泥浆槽壁稳定性评价的水平条分法[J]. 岩土工程学报,2013,35(6):1128−1133. XIA Yuanyou,PEI Yaoyao,WANG Zhide,et al. Horizontal slice method for stability of slurry trench[J]. Chinese Journal of Geotechnical Engineering,2013,35(6):1128−1133.

[17] FOX P. Analytical solutions for stability of slurry trench[J]. Journal of Geotechnical and Geoenvironmental Engineering,2004,130(7):749−758.

[18] LI Yuchao,PAN Qian,CLEALL P J,et al. Stability analysis of slurry trenches in similar layered soils[J]. Journal of Geotechnical and Geoenvironmental Engineering,2013,139(12):2104−2109.

[19] 黄茂松,王鸿宇,谭廷震,等. 地下连续墙成槽整体稳定性的工程评价方法[J]. 岩土工程学报,2021,43(5):795−803. HUANG Maosong,WANG Hongyu,TAN Tingzhen,et al. Engineering evaluation method for overall stability of slurry trenches[J]. Chinese Journal of Geotechnical Engineering,2021,43(5):795−803.

[20] 董书宁,李日润,虎维岳. 元宝山露天矿疏干优化设计[J]. 煤田地质与勘探,2000,28(5):38−41. DONG Shuning,LI Rirun,HU Weiyue. Optimal design of drainage borehole layout in Yuanbaoshan open pit[J]. Coal Geology & Exploration,2000,28(5):38−41.

[21] 姚道坤. 中国膨润土矿床及其开发应用[M]. 北京：地质出版社，1994.

[22] 上海市住房和城乡建设管理委员会. 基坑工程技术标准：DG/TJ 08–61–2018 J 11577—2018[S]. 上海：同济大学出版社，2018.

[23] MONTGOMERY D C，PECK E A，VINING G G. Introduction to linear regression analysis[M]. Hoboken：Wiley，2012.

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