大方形系数双尾船浅水下沉量与纵倾计算

用Rankine源面元法数值计算某内河大方形系数双尾船的浅水下沉量及纵倾,计算得到的船体纵倾值随航速的变化在浅水孤独波出现前与试验结果较一致,而下沉量的计算值则明显小于有关试验值,有关数值处理方法仍须进一步探讨。     

A review of the effect of a／W ratio on fracture toughness （Ⅰ）—experimental investigation in EPFM

Many experimental investigations have previously been performed and recently done on different shipbuilding structural steels where the specimens size and crack depth/specimen width (a/W) were varied. A series of interesting results have been gained. It is worthwhile to have a review on the effect of a/W ratio on fracture toughness, and further theoretical analysis is necessary. In this paper, experimental work in elasticplastic fracture mechanics (EPFM) was discussed. Tests had been carried out on 10 kinds of strength steels. Results showed that J _i and δ₁ values increased with decreasing a/W when a/W<0.3 for three-point bend specimens and that shallow crack specimens which have less constrained flow field give markedly higher values of toughness than deeply notched specimens. However, for a/W>0.3, the toughness was found to be independent of a/W. Slip line field analysis shows that for shallow cracks, the hydrostatic stress is lower than that from standard deeply cracked bend specimen which develops a high level of crack tip constraint, provides a lower bound estimate of toughness, and will ensure an unduly conservative approach when applied to structure defects especially if initiation values of COD/J-integral are used.     

穿越既有线超浅埋暗挖通道的质量监控

近年来,采用浅埋暗挖法修建的地下工程越来越多,它与明挖法、盾构法一样为地下工程的主要施工方法之一,而在超浅埋地层穿越既有线中采用暗挖法施工在国内是罕见的。本文重点介绍了我公司项目监理部在长春北站房地下通道的施工监理过程中,针对该工程超浅埋的特点,以新奥法的基本原理为基础,所采用的超浅埋暗挖法的控制重点及其质量监控措施。通过有效监控,既成功地保证了地下通道穿越了既有线路,保证了铁路运营的安全,同时也使该工程的质量达到优良标准,为今后穿越既有线超浅埋暗挖法施工的质量控制积累了经验。该工程的成功建成得到了业主及社会各方的高度评价。     

Collapse strength of hatch cover of bulk carrier subjected to lateral pressure load

A series of elastoplastic large deflection FEM analyses has been performed on hatch covers of bulk carriers subjected to lateral load. Two types of hatch covers are considered which are the folding type and the side-sliding type. For the folding-type cover, one size is considered which is for Handy size bulk carrier, whilst for the side-sliding-type cover, two sizes are considered which are for Panamax and Cape size bulk carriers. For each type, two hatch covers are selected which are designed in accordance with the old ICLL rule and new IACS rule, respectively. Calculated collapse strengths are compared with individual design loads, and a strength assessment is performed. On the basis of collapse behaviour observed in FEM analyses, a simple method is proposed to evaluate the collapse strength of a hatch cover subjected to lateral load. It is confirmed that the collapse strength is accurately predicted by the proposed method.     

浅埋暗挖隧道下穿结构物的施工沉降分祈

以北京地铁奥运支线起点（熊猫环岛站）区间隧道下穿健安桥的设计与施工为背景，分析浅埋暗挖隧道穿越地面结构物施工如何有效地控制沉降，探讨施工时应注意的关键环节和采取的措施，以此作为今后类似工程施工的依据和借鉴。     

富水砂卵石条件下大断面市政隧道浅埋暗挖法研究

文章以成都市人民北路北延线隧道为工程背景,在深入分析富水砂卵石地层特性的基础上,以洞口小净距段为重点,采用有限元法对大断面浅埋暗挖法隧道各区段进行数值模拟分析,获得了地层、初期支护和二次衬砌的受力特征以及一些可供类似工程参考的有价值的结论。     

关于浅水影响及其改善技术

通过浅水船型试验研究实例讨论浅水影响问题,强调内边界条件对船舶浅水性能的影响,并通过一例双体船的试验研究提出通过加装尾后水翼改善船舶浅水性能的技术方案。     

北京地铁浅埋暗挖施工坍塌的预防与处理

根据北京地质环境状况,分析了浅埋暗挖隧道施工坍塌的原因,以及预防及处理措施.浅埋暗控施工应以预防坍塌为主.出现坍塌时必须封闭掌子面,而后回填处理,切忌在坍塌后直接注入水泥浆.     

隧道偏压明洞错台成因及工程对策

明洞衬砌结构对隧道工程安全运营起到至关重要的作用,衬砌发生错台会对隧道洞口结构安全产生严重影响。针对华东地区某公路隧道偏压明洞段衬砌错台等病害,采用现场调研和数值模拟相结合的方法分析其产生原因,并提出相应的对策。研究成果表明： 隧道错台主要与边坡坡体浅层土体的侧压力有关,建议对边坡进行位移监测和对边坡坡脚位置及抗偏压墙处采用反压回填法进行处治,实施效果较好,可为类似隧道病害的整治提供参考。