极软岩隧道横洞开挖空间力学效应研究
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摘要
为研究极软岩隧道车行横洞交叉段施工力学特性,以大梁山特长公路隧道V级极软围岩段为依托,采用现场试验结合数值模拟试验分析其空间效应。研究断面现场监测结果表明:6个断面在深度为1 m、2m和3 m处内部围岩位移受横洞开挖影响较小,可忽略不计。拱腰和拱脚处钢支撑内力在横洞开挖后小幅增大,影响区集中于拱腰及以下部位,对拱顶部位影响较小。远离横洞侧拱脚、拱腰及拱顶处围岩压力与层间压力所受开挖影响很小,而近横洞侧拱腰处影响相对较大,在施工中应值得注意。数值试验结果表明,混凝土应力受横洞开挖影响主要表现为压应力增大,产生压应力增大区;围岩塑性区在开挖前有一定程度增大和区域改变,锚杆轴应力施工前后变化不大。
Based on the Daliangshan super-long tunnel constructed in V-grade rock mass,combining the in-situ test and numerical simulation test,the construction mechanics at the intersection of the horizontal adit in large-span and super-long highway tunnel in soft rock were studied. The in-situ monitoring results indicated that: the internal displacement at different depths in 6 study sections was slightly affected by adit excavation,which can be neglected. The inner force in steel support in tunnel hance and arch foot increased slightly after the excavation. In term of the influence area, it mainly concentrates on the hance and the following parts,which has little influence on the vault. Surrounding rock pressure and interlayer pressure in arch foot, hance and hance from the side of the adit was influenced slightly,while that in near side was influenced seriously. It should be worth paying attention to this situation in construction. The numerical results show that the influence of adit excavation on concrete stress is mainly manifested by increase of compressive stress and corresponding extension area. The plastic zone of the surrounding rock increases to a certain extent and some changes happened in distribution area,and the stress of the anchor shaft has little change before and after adit construction.
Based on the Daliangshan super-long tunnel constructed in V-grade rock mass,combining the in-situ test and numerical simulation test,the construction mechanics at the intersection of the horizontal adit in large-span and super-long highway tunnel in soft rock were studied. The in-situ monitoring results indicated that: the internal displacement at different depths in 6 study sections was slightly affected by adit excavation,which can be neglected. The inner force in steel support in tunnel hance and arch foot increased slightly after the excavation. In term of the influence area, it mainly concentrates on the hance and the following parts,which has little influence on the vault. Surrounding rock pressure and interlayer pressure in arch foot, hance and hance from the side of the adit was influenced slightly,while that in near side was influenced seriously. It should be worth paying attention to this situation in construction. The numerical results show that the influence of adit excavation on concrete stress is mainly manifested by increase of compressive stress and corresponding extension area. The plastic zone of the surrounding rock increases to a certain extent and some changes happened in distribution area,and the stress of the anchor shaft has little change before and after adit construction.
引文
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[3]吕青松,贺维国,方祖磊,等.水下长大隧道排水系统设计问题探讨[J].隧道建设,2016,36(11):1361-1365.
[4]郭佳奇,陈帆,刘开云.分水岭特长隧道运营通风测试与分析[J].公路,2016(8):239-244.
[5]把春红.大跨度隧道爆破开挖对邻近抗滑桩的影响研究[D].重庆:重庆交通大学,2017.
[6]杜峰,闫军,张学民,等.大跨度小净距隧道爆破振动影响数值模拟分析[J].铁道科学与工程学报,2017,14(3):568-574.
[7]赵秀绍,庄锦彬,徐长节,等.浅覆大跨度小净距隧道中岩墙及初支力学特性研究[J].公路交通科技,2015,32(12):100-107.
[8]王赤心.多车道高速公路隧道人行横洞疏散安全分析[J].公路交通科技,2015,32(11):100-106.
[9]宋金贵.横洞进正洞交叉口设计优化方案研究[J].隧道建设,2017,37(s1):168-173.
[10]王忠昶,姜雪峰,李亚洲.分岔隧道相交区围岩变形规律的数值模拟[J].辽宁工程技术大学学报,2017(6):598-603.
[11]李亚勇,邓怡虎,靳晓光,等.暗挖地铁车站施工通道与车站转换段施工方法研究[J].铁道科学与工程学报,2016,13(7):1352-1358.
[12]张志强,许江,万晓燕.公路长隧道与横通道空间斜交结构施工力学研究[J].岩土力学,2007,28(2):247-252.
[13]陈中.公路隧道行车横洞与正洞交叉连接部的设计简介[J].高速铁路技术,2000(1):1-4.
[14]朱方敏,蔡路军,韩芳,等.供水隧洞在上穿公路隧道开挖作用下的稳定性研究[J].公路工程,2016,41(1):188-192.
[15]徐学深.横通道施工对隧道衬砌结构影响的研究[J].土工基础,2012,26(2):47-50.
[16]钟善桐.钢管混凝上统一理论:研究与应用[M].北京:清华大学出版社,2006.