抗突涌稳定验算公式分析

基坑底承受高水头承压含水层水压力作用时需要进行抗突涌稳定验算,抗突涌稳定验算对基坑降水设计具有重要影响,决定了水头降低的程度,从而决定了降水井的布置和最终地面沉降值。规范中的抗突涌稳定验算公式基于压力平衡理论,Terzagh i针对砂土基坑的抗突涌稳定验算公式经推导具有与规范公式相同的形式。规范公式具有使坑底土体有效应力大于零、被动区小主应力大于零和水力坡降大于临界水力坡降的含义。     

Chemical heaving of soils

The physicochemical reactions that proceed during interaction between clayey minerals and acids and alkalis with the formation of heavily hydrated gel-like neogenic formations that heave clayey soils are addressed. The chemical heaving of sandy soils is examined. Methods used to restore structures deformed by heaving soils are analyzed. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 18–20, July–August, 1995.     

Analysis of piles and pile grillages on heaving soils

The concept of interaction between a heaving soil and individual and group piles and pile grillages, which makes it possible to determine both the magnitude of layer-by-layer uplift of soil around an individual pile and within a group of piles, and the piles themselves, is discussed. Specific examples of solutions are cited with comparison of predicted and actual values. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 2, pp. 25–30, March–April, 2006.     

Interaction of shallow strip foundations and heaving soils

Conclusions 1. The strip foundation rise caused by normal heave forces is linearly proportional to the pressure on the soil base, for all practical purposes.2. The pressure transmitted to the soil base affects the heave deformation over the entire freezing soil thickness.3. For identical loads on the foundations, the larger the underside width, the greater the foundation rise.4. The unit normal heave forces decrease as the underside width increases, and increase (nonproportionally) as the soil freezing depth increases.TsNIIÉPsel'stroi. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 4, pp. 5–7, July–August, 1987.     

Stabilization of tubular pile foundations in heaving soils

Theoretical and experimental substantiation is provided for one of the mechanisms responsible for the frost heaving of tubular pile foundations. A method is proposed for its neutralization by suppressing convection of water in the recesses of the piles using aqueous solutions of polyvinyl alcohol. In many cases, the method makes it possible to dispense with use of seasonal cooling devices, and, in turn lower the cost of, and simplify the process of stabilizing tubular pile foundations in heaving soils. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 25–29, November–December, 2006.     

地下城市通廊的防火设计

地下城市通廊具有形态复杂、周围衔接的空间多、内部功能和人员组成多样的特点,在现行的规范中没有直接的解决方案。对城市通廊的形态和特点进行了论述,对一种跨越多层、与地铁融合的多层城市通廊的形式提出了防火分隔和人员疏散的解决方案,并与常规设计进行分析对比。分析表明,城市通廊虽然放弃了传统的防火分区的概念,但是围绕商业进行防火分隔的方案不仅可以满足平面布局的要求,还可以更好地控制火灾蔓延的风险。人员疏散系统的设计要求很好地对现有不同规范之间进行了衔接,既保持了消防安全水平,也兼顾了项目的经济效益。     

地下大空间步行街火灾自然排烟有效性热烟试验

采用热烟试验方法研究某地下大空间步行街区采用自然排烟模式的有效性。火源面积为 2 m2 ,火源的功率约为1 500 kW,设置 3 处典型火源位置。结果表明,在自然排烟模式下,大部分烟气在热浮力作用下通过火源上方的自然排烟口排出至室外,仅在局部区域产生少量烟气的聚集、沉降现象。在模拟计算的人员疏散时间内,疏散路径及疏散出口能见度高,总体控烟排烟效果明显,烟气流动沿程的温度变化对人员疏散行为的影响不明显。     

Utilisation of underground pedestrian systems for urban sustainability

Underground pedestrian systems (UPS) have emerged as an urban phenomenon in the city centres of mega-cities, providing alternative walkways that are safe, accessible, efficient and pleasant for pedestrians. Despite many successful UPS in operation around the world, the application and performance of UPS are not yet well understood by local authorities. While previous studies debated the impacts on cities and people that the development of UPS would bring, an understanding of how to develop UPS to contribute to sustainable urban development, including economic viability, environmental livability and social equity, should be improved. This paper presents a detailed discussion of potential contributions and challenges in developing UPS within the context of sustainable urban development. It contains a comprehensive analysis of the relationship between UPS and urban development with regard to urban planning concepts such as the compact city, city resilience, sustainable transport and urban renewal, within the context of contemporary challenges such as the need to achieve economic sustainability, managing a non-renewable and vulnerable underground resource, and humanisation and social sustainability. It demonstrates why UPS development presents opportunities for and challenges to achieving economic viability, environmental livability and social equity, how to develop UPS so that they make effective contributions to sustainable urban development, and how the challenge of each issue has been addressed in light of the experiences of cities with UPS developments globally.     

石灰土冻胀特性试验研究

为考察石灰土在冻结状态下的物理力学性质 ,对不同石灰含量的石灰土的冻胀特性进行了试验研究。试验结果表明 ,石灰土的孔隙度和导水系数随着石灰含量的增加不断减小 ,而黏聚力则不断增加。在这种情况下 ,石灰土的冻胀率随着石灰含量的增加呈现显著减小的趋势。综合其它有关因素 ,从防止冻胀的角度来看 ,石灰含量的最优值约为 12 %～ 15 %左右     

两种地下步行通道火灾排烟模式比较研究

采用理论和FDS数值模拟结合的方法,研究地下步行通道发生火灾（1.5 MW）时,半横向排烟和纵向排烟对地下步行通道内火灾烟气蔓延的控制效果。研究表明,在排烟量相等、送风量不等的条件下,除火源正上方温度超过60 ℃外,半横向排烟模式下火灾参数未达到临界值,有利于行人向火源两侧逃生;纵向排烟模式将火灾参数均控制在临界指标以内,大部分烟气被控制在火源下风侧,有利于行人向上风侧逃生。地下步行通道火灾时,从人员逃生效率以及消防人员应急救援便捷性的角度出发,宜采用半横向排烟模式;从行人受危险因素不确定性影响的角度出发,宜采用纵向排烟模式。     

武汉剧院地下人行通道施工技术浅谈

针对武汉剧院地下人行通道工程埋深浅、路面活载作用频繁的特点,对明挖法、顶管法、盾构法和浅埋暗挖法进行了分析,根据工程特点及难点,确定采用浅埋暗挖法施工,并介绍了其具体施工方法,为类似工程提供参考借鉴。