Safety impact of backfill high slope on adjacent viaduct pier and roadbed in gully area
-
摘要: 某建设场地存在冲沟，需进行回填处理。回填区紧邻城市快速路高架桥，通过有限元模拟分析冲沟回填区基岩面走势、填筑高度及范围对桥墩及路基位移的影响，用以指导填方设计。分析结果表明：对于岩土界面平缓区域，回填过程中竖向位移主要集中在拟建场地回填区域，对桥墩区域的竖向位移影响较小；回填标高不超过路堤标高时，回填对路堤及桥墩水平位移影响较小，回填标高超过路堤标高后，路堤及桥墩水平位移值急剧增大，并超出桥梁位移控制标准，其影响区域主要集中在1.0～1.5倍回填高度范围内。对于岩土界面较陡区域，填方沿岩土界面产生分力，在桥桩两侧产生偏压，土体出现挤压或背离桩基的变形差异，地面产生不均匀沉降。 综合考虑桥墩与路基所处地质环境条件、校区土地利用、建筑整体布局及校区回填影响范围，对岩土界面较陡区域采用建筑架空处理，对岩土界面平缓区域采用回填边界退距+降低回填标高的综合治理方案，取得了较好的经济效果，工后监测显示路基及桥梁变形处于正常可控状态。Abstract: A construction site featuring a gully required backfilling. The backfill area was adjacent to an urban expressway overpass. Finite element simulation was employed to analyze the area on the influence of the bedrock surface trend, fill height, and filling range in the gully area on the displacement of the bridge pier and subgrade, thereby guiding the fill design. The analysis results indicate that: in areas with a gentle geotechnical interface, vertical displacement during the backfilling process was primarily concentrated within the backfill area, with minimal impact on the vertical displacement of the soil in the pier area. When the backfill elevation did not exceed the embankment elevation, the backfill had little effect on the horizontal displacement of the embankment and pier. However, once the backfill elevation surpassed the embankment elevation, the horizontal displacement of the embankment and pier increased sharply, exceeding the bridge displacement control standards. The affected area was mainly concentrated within a range of 1.0 to 1.5 times the backfill height. In areas with a steep geotechnical interface, the fill generated a component force along the geotechnical interface, resulting in biased pressure on both sides of the pile. This caused a differential deformation of the soil, either squeezing or moving away from the pile foundation, leading to uneven ground settlement. Considering the geological conditions of the pier and subgrade, site land use, overall building layout, and the influence range of the backfill, an overhead structural treatment was adopted for areas with a steep geotechnical interface. For areas with a gentle geotechnical interface, a comprehensive treatment scheme combining a setback distance at the backfill boundary and a reduction in the backfill elevation was implemented. This approach achieved favorable economic outcomes, and post-construction monitoring indicated that subgrade and bridge deformations were within normal and controllable limits.
-
表 1 数值模拟计算参数
计算参数 重度/(kN·m−3) 弹性模量/MPa 泊松比 黏聚力/kPa 内摩擦角/(°) 路基回填土 20 30 0.35 5 30 校区回填土 20 20 0.35 5 30 中等风化泥岩 24.72 3599 0.3 520 31.73 桩基及桥墩砼C40 25 32500 0.2 
下载: 导出CSV
表 2 施工荷载步
施工荷载步 荷载步说明 第1步 现状（桥墩及路基边坡已修建完成） 第2步 校区回填1（标高208～218 m） 第3步 校区回填2（标高218～226 m） 第4步 校区回填3（标高226～236 m） 第5步 校区回填4（标高236～244 m） 第6步 校区回填5（标高244～252 m） 第7步 校区回填6（标高252～255 m）
下载: 导出CSV
表 3 水平位移
荷载步 路堤最大水平
位移/mm桥梁区路堤水平
位移/mm桥墩水平位移
/mm回填1 2.2 0.2 0.2 回填2 6.3 0.9 1.1 回填3 12.7 4.4 4.8 回填4 23.5 10.3 10.9 回填5 35.8 16.0 17.6 回填6 39.7 17.9 19.7
下载: 导出CSV
表 4 最大水平位移
荷载步 路堤水平位移
/mm桥梁区路堤水平
位移/mm桥墩水平位移
/mm原设计 39.7 17.9 19.7 退距20 m 34.2 12.5 14.4 退距30 m 31.3 10.7 11.8 退距40 m 25.0 9.3 10.5 退距60 m 18.9 7.2 8.0
下载: 导出CSV
-
[1] 涂义亮, 刘新荣, 钟祖良, 等. 机场高填方边坡填筑过程的变形演化规律分析[J]. 地下空间与工程学报, 2019, 15(5): 1442-1450. (TU Y L, LIU X R, ZHONG Z L, et al. Evolution law of deformation of high fill slope of airport during filling process[J]. Chinese Journal of Underground Space and Engineering, 2019, 15(5): 1442-1450. (in Chinese)TU Y L, LIU X R, ZHONG Z L, et al. Evolution law of deformation of high fill slope of airport during filling process[J]. Chinese Journal of Underground Space and Engineering, 2019, 15（5）: 1442-1450. (in Chinese) [2] 杨校辉, 朱彦鹏, 周 勇, 等. 山区机场高填方边坡滑移过程时空监测与稳定性分析[J]. 岩石力学与工程学报, 2016, 35(S2): 3977-3990. (YANG X H, ZHU Y P, ZHOU Y, et al. Time-space monitoring and stability analysis of high fill slope slip process at a airport in mountain region[J]. Chinese Journal of Rock Mechanics and Engineering, 2016, 35(S2): 3977-3990. (in Chinese)YANG X H, ZHU Y P, ZHOU Y, et al. Time-space monitoring and stability analysis of high fill slope slip process at a airport in mountain region[J]. Chinese Journal of Rock Mechanics and Engineering, 2016, 35（S2）: 3977-3990. [3] 陈金明, 李 哲, 韩 映, 等. 斜坡地基上高填方边坡的变形及稳定性研究[J]. 路基工程, 2017(4): 52-56. (CHEN J M, LI Z, HAN Y, et al. Study on deformation and stability of high slope filled on slope foundation[J]. Subgrade Engineering, 2017(4): 52-56. (in Chinese)CHEN J M, LI Z, HAN Y, et al. Study on deformation and stability of high slope filled on slope foundation[J]. Subgrade Engineering, 2017（4）: 52-56. (in Chinese) [4] 侯俊伟, 唐秋元, 李杨秋, 等. 西南某山区机场高填方边坡稳定性研究[J]. 重庆交通大学学报(自然科学版), 2016, 35(3): 82-88. (HOU J W, TANG Q Y, LI Y Q, et al. Stability of high fill slope of an airport in southwest mountainous area[J]. Journal of Chongqing Jiaotong University (Natural Science), 2016, 35(3): 82-88. (in Chinese)HOU J W, TANG Q Y, LI Y Q, et al. Stability of high fill slope of an airport in southwest mountainous area[J]. Journal of Chongqing Jiaotong University (Natural Science), 2016, 35（3）: 82-88. (in Chinese) [5] 黄佳昕. 山区机场填方地基加强处理区域及顺坡填筑边坡稳定分析[D]. 北京: 清华大学, 2009. (HUANG J X. Slope stability of the improvement area in soft ground and fills on slope foundation in mountainous regions[D]. Beijing: Tsinghua University, 2009. (in Chinese)HUANG J X. Slope stability of the improvement area in soft ground and fills on slope foundation in mountainous regions[D]. Beijing: Tsinghua University, 2009. (in Chinese) [6] 唐 薇, 廖义玲, 梁 风. 基于强度折减理论对金工立交高填方边坡的稳定性分析[J]. 路基工程, 2013(1): 56-59. (TANG W, LIAO Y L, LIANG F. Analysis on stability of high-fill slope for Jingong overpass based on strength reduction theory[J]. Subgrade Engineering, 2013(1): 56-59. (in Chinese) doi: 10.3969/j.issn.1003-8825.2013.01.014TANG W, LIAO Y L, LIANG F. Analysis on stability of high-fill slope for Jingong overpass based on strength reduction theory[J]. Subgrade Engineering, 2013（1）: 56-59. (in Chinese) doi: 10.3969/j.issn.1003-8825.2013.01.014 [7] 曾锦秀, 胡卸文, 罗 刚, 等. 高填方填筑层数对填筑体沉降影响的数值模拟[J]. 山地学报, 2012, 30(4): 491-496. (ZENG J X, HU X W, LUO G, et al. Numerical simulation of influence of high fill filling layer number on settlement of filling body[J]. Journal of Mountain Science, 2012, 30(4): 491-496. (in Chinese) doi: 10.3969/j.issn.1008-2786.2012.04.016ZENG J X, HU X W, LUO G, et al. Numerical simulation of influence of high fill filling layer number on settlement of filling body[J]. Journal of Mountain Science, 2012, 30（4）: 491-496. (in Chinese) doi: 10.3969/j.issn.1008-2786.2012.04.016 [8] 陈 阳, 杜 刚, 高奋飞. 康定机场高填方地基变形与稳定性数值模拟[J]. 路基工程, 2011(2): 111-114. (CHEN Y, DU G, GAO F F. Numerical simulation on deformation and stability of high embankment of Kangding airport[J]. Subgrade Engineering, 2011(2): 111-114. (in Chinese) doi: 10.3969/j.issn.1003-8825.2011.02.036CHEN Y, DU G, GAO F F. Numerical simulation on deformation and stability of high embankment of Kangding airport[J]. Subgrade Engineering, 2011（2）: 111-114. (in Chinese) doi: 10.3969/j.issn.1003-8825.2011.02.036 [9] 曹集士. 攀枝花机场滑坡滑带土试验及滑坡滑动机理研究[D]. 成都: 西南交通大学, 2013. (CAO J S. The study on the sliding soil testing and the sliding mechanism of Panzhihua airport landslide[D]. Chengdu: Southwest Jiaotong University, 2013. (in Chinese)CAO J S. The study on the sliding soil testing and the sliding mechanism of Panzhihua airport landslide[D]. Chengdu: Southwest Jiaotong University, 2013. (in Chinese) [10] 满 立, 刘子昂, 别江波. 西南某机场高填方地基变形与稳定性数值模拟[J]. 路基工程, 2015(1): 181-183. (MAN L, LIU Z A, BIE J B. Numerical simulation on deformation and stability of high embankment for an airport in the southwest[J]. Subgrade Engineering, 2015(1): 181-183. (in Chinese)MAN L, LIU Z A, BIE J B. Numerical simulation on deformation and stability of high embankment for an airport in the southwest[J]. Subgrade Engineering, 2015（1）: 181-183. (in Chinese) -
图(11) / 表(4)
计量
- 文章访问数: 8
- HTML全文浏览量: 3
- PDF下载量: 1
- 被引次数: 0
