滚石冲击荷载下棚洞结构动力响应   总被引：5，自引：0，他引：5  

何思明  沈均  吴永 《岩土力学》2011,32(3):781-788

钢筋混凝土棚洞结构是西部滚石灾害多发区最为有效的滚石防护结构,一般通过在棚洞顶部铺设一定厚度的砂砾石垫层来达到缓冲吸能的目的。在棚洞结构设计中,确定滚石冲击力大小是关键,而目前国内外尚无合理的计算公式,严重地影响了滚石棚洞结构工程应用。由于滚石冲击能量大,冲击时间短暂,涉及到结构大变形和复杂的能量转换关系,因而滚石冲击荷载下棚洞结构的动力响应研究难度较大。以实际滚石棚洞结构为原型,采用动力有限元对滚石冲击过程进行了数值仿真,研究滚石在不同冲击角度下棚洞结构的动力力学响应,为滚石防护工程设计提供理论基础。  相似文献   

季冻区棚洞结构建设技术     

王文华  王清  赵文丁 《吉林大学学报(地球科学版)》2011,41(1):168-171

为保护高速公路傍山路段的边坡和自然环境,将棚洞按三心圆拱加拱形顶板的斜柱支撑体系建设。根据棚洞的不同埋深,分别采取明挖、护拱和暗挖等开挖方式,避免由于大开挖引起的边坡或山体不稳定而产生的落石、滑坡、滑塌等灾害发生。对棚洞最不利位置的平面应变弹性数值模拟分析表明：在季冻区的气候条件下将棚洞按三心圆拱加拱形顶板的斜柱支撑体系建设是合理的,其主拉应力为1.440 MPa,主压应力为3.240 MPa,合位移为2.1 mm,在安全上满足JTG D70-2004公路隧道设计规范要求。采用适合季冻区的三心圆拱斜柱式棚洞结构型式和防、排水措施,为季冻区傍山公路建设提供防灾环保型建设理念的经验。  相似文献   

阿里山森林铁路隧道复建工程的设计与施工探讨     

李嵘泰  刘弘祥  魏铭辉  黄崇仁  连祥益  沈宜庆  廖一光 《岩土力学》2014,35(8):2325-2334

2009年8月8日莫拉克台风重创南台湾,嘉义阿里山区72 h的累积雨量高达2 500 mm以上,百年历史的阿里山森林铁道因沿线路基严重流失而停驶。其中两处大崩塌路段的复建工程以顺应自然为原则,采取迂回隧道方式避开崩塌区,需克服沿线地质变化及地下水问题,评估结果是以凿岩机工法及钻爆工法进行开挖。两座隧道的西口段崩积层分别长达109.8、99 m,是隧道开挖阶段的关键地段。隧道开挖支撑设计系依据台湾岩体分类与支撑系统（PCCR系统）及新奥工法的理念,沿线采用先进支撑材料包括超前管棚钢管、桁型钢支护、钢纤维喷射混凝土及自钻式锚杆等,除了可确保施工安全外,亦可提高施工进度。目前两隧道均已贯通且变形量控制均符合安全,说明隧道采用先进支撑方式穿越破碎崩积层段的成效良好,其研究结果可为相关工程设计提供参考。  相似文献   

半硬半软岩隧道塌方的力学特性及处理方法分析   总被引：1，自引：0，他引：1  

喻军  刘松玉  童立元 《工程地质学报》2009,17(2):263-267

由于蛟岭隧道出口横断面一半为硬岩,结构完整,而另一半为软岩,为风化岩层,且较为破碎,所以在隧道开挖时,硬岩一侧刚度较大,变形较小,自稳能力大;软岩一侧与之相反,遇水软化,流变性明显,所以在软硬岩交界面处,产生滑移,导致塌方,从而在软岩一侧采取了地表加固和掌子面管棚注浆的处理,形成了与硬岩接近的强度,使隧道周围形成一个承载环,并对处理段进行了监测,监测数据分析表明处理后迅速达到稳定。  相似文献   

冬暖大棚建棚指标计算     

郑国喜 《气象科技》2002,30(2):112-114

利用数学与气象学的有关理论 ,对鲁南地区冬暖大棚的建棚指标进行了计算 ,得出棚体后坡适宜仰角为 43°,适宜跨度为 8～ 9m ,棚体前张角为 46°。计算结果表明建棚指标与地理纬度有关 ,该计算方法适用于不同地理纬度地区建棚指标的计算 ,并给出垂线投影测定子午线的方法  相似文献   

三架岭公路隧道进口洞口段施工技术     

宋国生  吕金林  吕振洲 《探矿工程》2003,30(4):65-66

介绍了本溪市三架岭公路隧道的进洞方法，通过采用边仰坡加固、管棚预加固、正台阶侧壁导坑法开挖等措施，保证了隧道进洞的顺利完成。  相似文献   

采用小管棚技术处理中小型隧洞塌方   总被引：1，自引：0，他引：1       下载免费PDF全文

廖春元 《探矿工程》2003,30(5):63-64

湖南省岳阳市铁山灌区引水工程金明冲隧洞在施工时发生大塌方。通过对3种处理方案的比选，采用了小管棚支护技术。介绍了小管棚支护施工技术工艺，并对其稳定性进行了验算。  相似文献   

仙宇屯景区危岩体稳定性分析及治理措施          下载免费PDF全文

胡才源  章广成  李小玲  孙全福  张忠 《贵州地质》2018,35(2):153-157,144

为保障景区游客及旅游设施的安全,本文运用无人机遥感航空拍摄,生成实景三维立体模型,宏观分析危岩体的破坏模式。基于三维激光扫描技术,对仙宇屯东南面和西南面危岩带进行精准量测,获取危岩体几何尺寸、结构面产状、方量等崩塌参数,对危岩体的稳定性进行定性评价。结果表明,天然工况下,仙宇屯两处危岩处于稳定状态;暴雨工况下,处于不稳定状态。因危岩体与旅游栈道形成垂直威胁,分析计算采用长廊式的板棚治理措施以达到融入自然生态环境目的。  相似文献   

Wind tunnel experimental study on shed tunnels to prevent and control blowing snow on highways北大核心CSCD     

马磊  刘健  冉武平  胡智轩  李在蓝  俞祥祥 《冰川冻土》2022,44(2):726-734

There is a severe phenomenon of blowing snow by wind in winter in Mayitas area of Xinjiang. Road traffic interruptions and casualties caused by wind and snow disasters often occur. The existing engineering measures can alleviate the problems of low visibility and problems with accumulating snow on pavement caused by wind and snow to a certain extent, but cannot completely eliminate the impact. Aiming at the problem that the blowing snow disaster difficult to be completely cured under strong wind conditions, a shed tunnel engineering treatment scheme is proposed, and a wind tunnel simulation experiment is carried out on the shed tunnel form and snow prevention scheme at the entrance of the tunnel. The wind tunnel experimental section is 8 m long, 1. 3 m horizontally wide and 1 m high. The shed tunnel model is made by 1:60 scale 3D printing method, the snow barrier model is made of wooden strips, and the simulation medium is made of fine sand, refined salt and sawdust. Firstly, three kinds of shed structures, including fully enclosed, overhanging and ventilated, were simulated under the condition of 90° wind direction, and compared with the form of blowing snow stacking. Three parameters for similarity were used:density, particle size and stacking shape. The similarity is determined by weighted Euclidean distance between simulation medium and blowing snow, the similarity of the slump angle of the predecessors is verified, and the most suitable medium for simulating blowing snow is deduced. According to the experimental results, combined with the actual situation of wind blowing and snow disasters in Mayitas, flow field of the closed shed tunnel by a wind direction angle of 30° has been separately conducted with or without protective measures. The results show that when the wind tunnel stacking experiment is used to study the deposition state of blowing snow under non-low temperature conditions, the sawdust has good similarity with the blowing snow in the process of wind and snow movement. A large amount of medium was poured into the ventilated shed during the experiment, which proved that its anti-wind and snow performance was not ideal. By contrast, the closed shed and the overhanging shed have better wind and snow prevention effects. The snow barrier has a good blowing snow inhibition function at the entrance. From the stacking experiment, in the comparison with and without snow barrier, volume of the medium in the shed is very different, which proves that the snow barrier can effectively prevent the blowing snow from entering the shed. Among them, the difference in wind speed inside and outside the shed is obvious, which proves that snow barrier can significantly reduce the wind speed outside the shed and has the function of inhibiting the formation of weak wind areas inside the shed. The study has confirmed that the shed tunnel project with suitable snow barrier layout plan for tunnel entrance protection is an effective means to control wind and snow disasters. For highway traffic in Xinjiang, it is a feasible solution to use shed tunnel engineering to control blowing snow disasters. After dealing with the snow deposition at the entrance of shed tunnel, the shed tunnel engineering form of low-cost environment integration and the vehicle operation safety guarantee measures of long-distance shed tunnel are the problems that need to be solved in the future. © 2022 Tianjin Press of Chinese Herbal Medicines. All rights reserved.  相似文献   

城市旧住宅区改造三方利益关系探讨:以深圳市为例     

严东  郭源园  梁勇林 《地理研究》2021,40(3):779-792

结合深圳的旧住宅区改造实践,以土地使用权、土地发展权及房屋价值解读为基础,探讨政府、开发商以及业主在旧住宅区改造过程中应该扮演的角色,并进一步分析当前深圳市旧住宅区改造中政府、开发商以及业主三方角色的现实关系。在此基础上,针对当前深圳市的三种旧住宅区改造模式中的三方关系进行对比剖析,发现传统市场主导模式下的旧住宅区改造中存在三方角色的“缺位”“越位”与“失位”行为是导致旧住宅区改造难以推进的核心症结所在。同时基于相对成功的鹿丹村改造模式,提出基于角色“归位”的三方角色利益平衡及“片区统筹协调”的旧住宅区改造愿景,以期为深圳市乃至全国其余大中城市中现实存在的旧住宅区改造问题提供些许思路和参考。  相似文献