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91.
宁波野猪山公路隧道右线出口段埋深浅、围岩差,采用岩土控制变形工法施工。该工法在我国公路隧道施工中几乎未有使用。本文通过数值模拟和现场监测数据对比分析,得出:1)隧道地表沉降的开挖空间效应约为0.6倍跨径,并据敏感程度划分为沉降敏感区、敏感过渡区、稳定区3个区域;2)隧道拱顶沉降约60%发生在掌子面到达监测断面前,开挖空间效应稍大于单倍跨径;3)隧道掌子面挤出变形呈外凸抛物面形态,建议施工中纤维锚杆的搭接长度设为6 m,并据挤出变形发展速率划分为快速发展、稳定发展、基本稳定3个阶段。  相似文献   
92.
马悦  廖昉  朱志武  杨柳 《隧道建设》2017,37(8):1011-1017
为确定在冻土冻结过程中冻结影响范围与冻结时间的关系,将人工冻土冻结过程拆分为土体表面的热散失和冻结管的冻结2个过程,并以热势能及热势能耗散过程中的平衡方程分析上述关系。为确定冻结管间距的合理取值,引入热势能理论并计算当量热阻,建立在多个冻结管影响下微元体的冻结时间方程,提出一种在多个冻结管作用下冻结影响范围与冻结时间的关系的计算方法及冻结管布置间距的确定方法。通过实例分析了人工冻土厚度的计算方法,以数值模拟方法比较了不同冻结管布置对冻结时间的影响。上述研究成果深化了人工冻土理论研究与实际应用之间的关系。  相似文献   
93.
亚急性感染性心内膜炎易侵犯瓣膜,造成瓣膜损坏,瓣膜置换手术疗效肯定,术后并发恶性心律失常较为罕见。我院于2004年9月收治1例亚急性感染性心内膜炎瓣膜置换术后并发恶性心律失常患者。现报告如下。  相似文献   
94.
目的总结利用自体心包片作为修补或管道连接材料用于心血管畸形或病变矫治中的临床经验。方法850例患者在全麻下实施心脏、血管直视手术。术中获取大小合适的心包片,应用于间隔缺损修补、房间隔重建、流出道加宽、外管道制作与吻合,以及瓣膜成形等手术。结果手术死亡11例,均与心包片应用无关。痊愈出院839例,术后3~6个月内门诊体检,心动超声图检查218例(约占26%),2例仍存在术前的三尖瓣中度关闭不全,1例右心功能不全,其余疗效尚满意。无1例发生因选用心包所致的相关并发症,如动脉瘤样膨出、补片残余漏等。结论自体心包片是心血管疾病矫治中不可多得的修复材料,早期疗效良好,晚期效果有待于进一步观察研究。  相似文献   
95.
随着心脏外科技术的日益成熟 ,手术安全性的不断提高 ,术后美观、少痛苦等问题越来越受到重视。微创外科具有手术损伤小、术后恢复快、疼痛轻、美观效果好的特点 ,近年来逐步被心外科医师所推崇应用。自 1996年 3月至 2 0 0 1年 5月 ,我们采用微创伤技术行先天性心脏病畸形矫治 ,瓣膜置换及冠状动脉旁路移植 (coronaryarterybypassgrafting ,CABG)等手术 82例 ,取得了较好的效果 ,现总结报告如下。1 临床资料 1.1 一般资料 本组男 37例 ,女 45例 ;年龄 4~ 5 6岁。体重 14.5~ 70 .8kg。先天性心脏病…  相似文献   
96.
The cross sea channel for the Qiongzhou Strait not only provides a solution for transportation, but also plays an important role in the political and economic development of the region. In addition, the project has an extensive impact on many fields, such as energy, national defense, science and technology, opening up and reform, comprehensive utilization and so on. It is a significant project to enhance China′s comprehensive national strength, defend the country′s territorial integrity and promote regional economic development. The geological conditions across the Qiongzhou Strait are complex. A large amount of existing engineering geological information and hydrogeological data are collected, based on which the seismic impact on subsea tunnels and the main geological conditions including tectonic structures are analyzed. Different options crossing the Qiongzhou Strait have been considered and compared in terms of engineering geology, environmental condition, as well as the construction feasibility. The analystical results indicate that a subsea tunnel has more advantages over a bridge. Because more complicated technical difficulties have to be solved for a highway tunnel which would potentially increase construction and operation costs, a railway tunnel scheme is recommended. Vehicles can be carried by trains through the Qiongzhou Strait railway tunnel. Based on the seabed topography and geological conditions, four preliminary railway tunnel routes are proposed. After a comprehensive comparative analysis, the railway tunnel route Ⅱ is identified to be superior to other alternatives and should be the basis for determining the final tunnel layout. The proposed tunnel cross section includes two railway tunnels and one service tunnel. All the three tunnels have the same structural form and dimension and will be constructed by shield.  相似文献   
97.
In order to resolve the challenges encountered in the construction of Gaoligongshan Tunnel such as soft rock deformation of inclined shafts, water drainage and protection of vertical shafts, TBM jam in crossing areas with adverse geology, solutions and key construction techniques are developed through theoretical analysis, field test, scheme optimization and staged review and summary. The performance results of field practice show that: (1)the goal of no damages and no replacement of the primary support can be achieved by adopting the comprehensive deformation prevention technique of "ring support early formation and quick closure", setting of proper excavation line curvature, and reinforcing of support; (2)the risk of vertical shaft flooding during construction in water rich weak granite can be greatly reduced by adopting the water control principle of "exploration for any excavation, plugging as the main method, and supplemented with drainage method" and the key pre grouting technique of S shaped deep boreholes; (3)the open type TBM can quickly and safely pass through the unfavorable mylonitic granite stratum by adopting the small pilot tunnel construction method, thus the fast and high efficiency construction performance of TBM can be fully utilized.  相似文献   
98.
In order to guarantee the stability of surrounding rock and support structure of super large span tunnel and realize quantification of support structure design, the optimal excavation contour line shape is obtained based on study of influence of initial ground stress on bearing arch of surrounding rock; a new quantitative design method, in which the surrounding rock is regarded as an arch structure, bolts, cables, shotcrete and lining are designed to satisfy the intensity, rigidity and stability of the arch structure, is presented to design the support structure system. The method has been successfully applied to super large span tunnel of Badaling Great Wall Station on Beijing Zhangjiajie High speed Railway; and the applicable results show that the maximum accumulative settlement of crown top of large span section is only 17.3 mm, and the relative subsidence of crown top is only 0.09%, which can meet safety requirements.  相似文献   
99.
为研究偏压荷载对箱型明洞结构受力影响,为该类明洞结构的设计提供理论依据,以某道路开孔箱型明洞工程为例,采用ANSYS有限元数值模拟方法进行计算分析,综合研究结果表明: 1)偏压回填箱型明洞靠山侧墙底部和外侧墙顶部受力较大,设计配筋时需要加强; 2)靠山侧墙背回填土侧压力对明洞结构受力影响较大,改善回填材料内摩擦角大小可以有效降低明洞结构内力,当内摩擦角增大到47°时最为经济; 3)可以通过在明洞洞顶回填EPE的方式减轻洞顶冲击荷载,降低明洞内力,最优回填厚度为0.9 m。  相似文献   
100.
周华贵  何一韬 《隧道建设》2018,38(11):1830-1835
海底岩溶隧道勘察、设计难度大,施工风险高。以大连市地铁5号线海底岩溶大直径盾构隧道为研究对象,首次采用“跨孔CT物探+钻探”的海底隧道岩溶勘察方案,通过有限元计算确定海底岩溶隧道加固范围,通过抗浮计算确定岩溶隧道基底加固标准,提出海底岩溶的海面预处理具体实施方案和盾构针对性设计方案,从而形成一整套海底岩溶盾构隧道勘察、设计及岩溶处理方案。  相似文献   
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