赵亮亮, 宁贵霞, 李盛, 等. 2020.基于EPS板减载的不同矢跨比高填黄土明洞土压力及影响因素离散元分析[J].工程地质学报, 28(6): 1430-1438. doi: 10.13544/j.cnki.jeg.2019-515.
    引用本文: 赵亮亮, 宁贵霞, 李盛, 等. 2020.基于EPS板减载的不同矢跨比高填黄土明洞土压力及影响因素离散元分析[J].工程地质学报, 28(6): 1430-1438. doi: 10.13544/j.cnki.jeg.2019-515.
    Zhao Liangliang, Ning Guixia, Li Sheng, et al. 2020. Discrete element analysis of earth pressure and influencing factors for high-filled cut-and-cover tunnel with different height-span ratios based on EPS load reduction[J]. Journal of Engineering Geology, 28(6): 1430-1438. doi: 10.13544/j.cnki.jeg.2019-515.
    Citation: Zhao Liangliang, Ning Guixia, Li Sheng, et al. 2020. Discrete element analysis of earth pressure and influencing factors for high-filled cut-and-cover tunnel with different height-span ratios based on EPS load reduction[J]. Journal of Engineering Geology, 28(6): 1430-1438. doi: 10.13544/j.cnki.jeg.2019-515.

    基于EPS板减载的不同矢跨比高填黄土明洞土压力及影响因素离散元分析

    DISCRETE ELEMENT ANALYSIS OF EARTH PRESSURE AND INFLUENCING FACTORS FOR HIGH-FILLED CUT- AND -COVER TUNNEL WITH DIFFERENT HEIGHT-SPAN RATIOS BASED ON EPS LOAD REDUCTION

    • 摘要: 利用离散元计算软件PFC2D模拟EPS板减载措施下不同矢跨比(0.4~0.9)拱形明洞的土压力变化状况,从微观角度对减载明洞上方垂直土压力、竖向位移、侧面水平土压力及颗粒间接触进行深入分析,明确内部土体的土压力变化规律。同时,对最佳矢跨比下的不同槽宽比和边坡坡角进行参数敏感性分析。结果表明:EPS减载下,明洞顶出现“土拱效应”,明洞顶垂直土压力沿水平方向呈“U”形变化,竖向位移呈“V”形减小,明洞侧面水平土压力沿竖向呈斜“S”形变化;在最佳矢跨比0.8下,颗粒间接触呈现接触力最小、配位数最小、孔隙率最大的良好状态。当槽宽比越大时,平均垂直土压力越大,竖向位移差和平均水平土压力越小,颗粒间接触状况越差;当边坡坡角越大时,平均垂直土压力越小,竖向位移差和平均水平土压力越大,颗粒间接触状况越好。研究成果可为沟谷地区高填减载明洞结构选型和施工提供参考。

       

      Abstract: Using the discrete element software called PFC2D, we simulate the earth pressure variation of arched cut-and-cover tunnel with different height-span ratios(0.4 to 0.9)under the EPS load reduction measures. Moreover, we also analyze the vertical earth pressure and vertical displacement on top of the cut-and-cover tunnel, horizontal earth pressure on sides of the cut-and-cover tunnel and soil particle contact at the micro level. We understand the change of earth pressure in the inner soil. Meanwhile, we analyze the effects of different groove width ratios and slope angles on earth pressure at the optimal height-span ratio. The result shows that the top of arched cut-and-cover tunnel appears soil arch effect when there is EPS load reduction. The vertical earth pressure on top of the cut-and-cover tunnel changes from the center of the model to the sides with a U-shaped distribution. The vertical displacement on top of the cut-and-cover tunnel decreases from the center of the model to the sides with a V-shaped distribution. The horizontal earth pressure on sides of the cut-and-cover tunnel changes with an inclined S-shaped distribution along the vertical direction. At the optimal height-span ratio of 0.8, the soil particle contact shows a good level, where the contact force and coordination number are the smallest, and the porosity is the largest. In addition, with the increase of the groove width ratio, the average vertical earth pressure gradually increases, the vertical displacement difference and the average horizontal earth pressure gradually decrease, and the soil particle contact level becomes worse. With the increase of the slope angle, the average vertical earth pressure gradually decreases, the vertical displacement difference and the average horizontal earth pressure gradually increase, and the soil particle contact level becomes better. The results can provide reference for the selection and construction of high-filled loess cut-and-covert tunnel in the valley area.

       

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