地铁隧道复合式结构可靠度简化分析方法研究

应用荷载-结构模型,建立了地铁矿山法区间隧道二次衬砌结构截面可靠度功能函数,根据北京地铁4,5和10号线勘探地质地层物理力学性质统计特征,利用蒙特卡罗方法进行区间隧道结构可靠度分析。探讨了在长期自然环境下复合式衬砌的初期支护与二次衬砌各自的作用,认为二次衬砌承受运营阶段的全部荷载,初期支护的作用仅仅是改善了二次衬砌的工作环境,改善后二次衬砌周围的弹性抗力系数应适当提高,这样处理不仅可简化计算工作,也符合衬砌结构的实际工作情况。     

Seismic fragility assessment of nonstructural components in unreinforced clay brick masonry buildings

The results of an investigation of the probability of earthquake damage to nonstructural unreinforced masonry (URM) components are presented. The components include parapets, chimneys, and out-of-plane loaded facades typical of low-rise pre-1940 construction in Australia and New Zealand. The study is based on a street survey of component geometry, in situ data on material strength, and simplified mechanical models. Uncertainties in capacity and demand were quantified based on, respectively, stochastic and deterministic approaches. The damage probabilities were compared with relevant guidelines and empirical damage data from three earthquakes. The study established a link between the qualitative damage states reported in existing guidelines and the quantitative URM component damage states. While some median damage state thresholds correlated well with the data from the guidelines, a larger dispersion value was found in the current study due to the large variations in component properties. Comparisons with empirical data suggest that the developed fragility data provide a realistic estimate of nonstructural component damage that occurred in similar buildings, with a reasonable level of conservatism. The outcome is useful in rapid assessment of the seismic risks due to nonstructural component collapse in URM precincts.     

三峡库区农民自建房抗震性能调查

通过实地调查与问卷调查相结合的方式,从结构类型及层数、建设场地选址、建筑材料、地基基础和抗震构造措施、墙体、楼屋盖、设计施工、质量通病、抗震能力及农民抗震意识等方面对三峡库区农民自建砖混房屋的抗震性能进行调查研究,结果发现农民自建房存在选址随意、材料质量低劣、缺乏正规的设计指导、施工方式粗放、质量通病等严重影响抗震性能的问题,并提出了编制村镇民居选址、规划和设计指南,加强村镇建筑材料的质量监管,建立农村民居抗震减灾技术服务网等措施和建议。调查结果为三峡库区农民自建房的抗震鉴定和加固改造提供参考。     

有冻土层场地上多层砖房的震害预测方法

以一个６层砖结构和四种场地共同组建成四个结构－地基一体化计算模型,输入唐山地震基岩地表的余震记录,计算融土场地、有冻层场地和刚性地基三种情况下结构的地震反应,通过结构基底等效输入和结构地震反应内力的比较,作者认为,对绝大多数中软场地,用现行的刚性地基假设,作多层砖房震害预测是偏于安全的。     

九景公路雁列山隧道复合式衬砌防排水的设计与施工

九江至景德镇高速公路雁列山隧道防排水系统采用初期锚喷砼和二次模注的复合衬砌形式。介绍了其设计、施工及质量缺陷的整治措施。     

石墨尾矿烧结砖制备工艺及性能研究

山东青岛南墅地区是我国优质石墨的生产基地。石墨资源的开发,对当地经济发展产生了明显的带动和促进作用。但是,石墨选矿厂排放的大量固体尾矿,不仅占用了宝贵的农田,也对区域生态环境产生了不利影响。石墨选矿厂投产以来排放的尾矿,已占用了数十公顷的土地,其中最大的一个尾矿堆场,面积达１０公顷,体积约３２万ｍ３。裸露于地表的泥沙状尾矿粉末,随风飘扬,极易形成扬沙天气;在多雨季节,大量降水又形成泥沙流,危及周围农田。为解决尾矿带来的环境问题,石墨矿及当地政府每年都要花费巨资和人力对尾矿进行掩盖,但治理效果不佳…     

海南岛砖红壤中重金属元素的分布特征及其环境效应

选择海南岛占地面积广、发育典型的砖红壤作为研究对象，探讨砖红壤发育过程中重金属元素的组成特征，分析不同地区砖红壤剖面重金属元素含量的纵向变化规律，厘定不同剖面不同层位重金属元素的富集规律及其成因，并阐述土壤重金属污染的环境效应及其与人类健康之间的相关关系。     

高水位隧道堵水限排围岩与支护相互作用分析

为了保护环境并尽可能降低衬砌结构所受的水压力,提出高水位山岭隧道应采取“以堵为主,限量排放”,即“堵水限排”的防排水设计原则。但对于堵水限排情况下衬砌结构的设计,目前尚没有规范可依,这是目前隧道设计施工亟待解决的问题。在隧道力学和渗流力学的基础上进行理论分析,研究渗流应力耦合作用下围岩的力学特性,利用特征曲线法分析了不同排放量下围岩与支护的相互作用,并与数值方法计算结果进行对比。计算结果表明：不同排水量下围岩特性曲线不同,支护阻力也不同,不同排水条件下围岩有效切向应力和有效径向应力的变化很明显,排水对围岩应力以及支护体系受力的影响是不容忽视的。另外,传统隧道设计方法在全排水时完全不考虑水的作用是不安全的。所得结论可为堵水限排衬砌结构设计提供理论依据。     

河北省李家沟公路隧道施工设计

李家沟公路隧道采用短台阶及全断面开挖;钢筋骨架网衬砌模注砼及初期锚喷砼支护,采用水泥裹砂半湿式喷砼法,衬砌分２序进行;采用光面控制爆破。     

Effects of tunnelling on existing support systems of perpendicularly crossing tunnels

The interactions between perpendicularly crossing tunnels in the Sydney region are investigated using a full three-dimensional (3D) finite element analysis coupled with elasto-plastic material models. Special attention is paid to the effect of subsequent tunnelling on the support system, i.e. the shotcrete lining and rock bolts, of the existing tunnel. The results of the analysis show that in a region such as Sydney, with relatively high horizontal stresses, installation of the new tunnel causes the shotcrete lining of the existing tunnel to be in tension in the side facing towards the tunnel opening and in compression at the crown and invert. The pre-stressed rock bolts are usually tensioned more in the sections closest to the tunnel opening. For this particular study, if a new tunnel is driven perpendicularly beneath an existing tunnel, significant increases are induced in the bending moments in the shotcrete lining at the lateral sides of the existing tunnel and in the axial forces at its crown and invert. The increase in side bending moments causes further tensile cracking but the crown and invert stresses remain within the thresholds for both compressive failure and tensile cracking for shotcrete lining of typical concrete quality. Moreover, the driving of the new tunnel causes the tensile forces in the existing side rock bolts to increase and those in the existing crown rock bolts to decrease. In contrast, if the new tunnel is driven perpendicularly above the existing tunnel, compressive failure of the existing shotcrete lining is induced at the crown of the deeper tunnel for concrete of typical capacity and a significant tensile force increase of the existing rock bolts around the crown. It is concluded that in order to ensure the stability of the existing tunnel, local thickening is needed at the sides of the existing shotcrete lining if the shallow tunnel is installed first and local thickening is needed at the crown if the deep tunnel is installed first.