Evaluating building fire safety through egress prediction: A standard application in Japan

Egress calculation, or predicting human flow during egress, is widely applied in Japan using a standardized method for evaluating the fire safety of building plans. This paper illustrates the methods involved in egress calculation using concrete examples and a sample plan. The egress calculation plays an important role in evaluating building plans and in complementing existing fire regulations. However, further investigation needs to be done into human behavior and how it factors into egress.     

佛山某隧道工程的基坑监测技术

介绍了佛山某隧道工程的基坑概况,对隧道基坑桩顶水平位移、支护桩深层侧向位移、钢管内支撑的轴力、坑外地下水位、房屋沉降与倾斜等方面进行了监测,并对其监测结果分别进行了分析,以供类似工程参考。     

How far droplets can move in indoor environments--revisiting the Wells evaporation-falling curve

A large number of infectious diseases are believed to be transmitted between people via large droplets and by airborne routes. An understanding of evaporation and dispersion of droplets and droplet nuclei is not only significant for developing effective engineering control methods for infectious diseases but also for exploring the basic transmission mechanisms of the infectious diseases. How far droplets can move is related to how far droplet-borne diseases can transmit. A simple physical model is developed and used here to investigate the evaporation and movement of droplets expelled during respiratory activities; in particular, the well-known Wells evaporation-falling curve of droplets is revisited considering the effect of relative humidity, air speed, and respiratory jets. Our simple model considers the movement of exhaled air, as well as the evaporation and movement of a single droplet. Exhaled air is treated as a steady-state non-isothermal (warm) jet horizontally issuing into stagnant surrounding air. A droplet is assumed to evaporate and move in this non-isothermal jet. Calculations are performed for both pure water droplets and droplets of sodium chloride (physiological saline) solution (0.9% w/v). We calculate the droplet lifetimes and how droplet size changes, as well as how far the droplets travel in different relative humidities. Our results indicate that a droplet's size predominately dictates its evaporation and movement after being expelled. The sizes of the largest droplets that would totally evaporate before falling 2 m away are determined under different conditions. The maximum horizontal distances that droplets can reach during different respiratory activities are also obtained. Our study is useful for developing effective prevention measures for controlling infectious diseases in hospitals and in the community at large. PRACTICAL IMPLICATIONS: Our study reveals that for respiratory exhalation flows, the sizes of the largest droplets that would totally evaporate before falling 2 m away are between 60 and 100 microm, and these expelled large droplets are carried more than 6 m away by exhaled air at a velocity of 50 m/s (sneezing), more than 2 m away at a velocity of 10 m/s (coughing) and less than 1 m away at a velocity of 1 m/s (breathing). These findings are useful for developing effective engineering control methods for infectious diseases, and also for exploring the basic transmission mechanisms of the infectious diseases. There is a need to examine the air distribution systems in hospital wards for controlling both airborne and droplet-borne transmitted diseases.     

爆炸荷载作用下深部块体变形运动规律研究

首先分析岩石作为地质体的非连续构造的块体性特征和运动变形机制，通过引入理论计算模型，总结块体运动和变形的理论计算方法；然后，运用数值手段研究爆炸荷载作用下块体运动和变形的基本规律，再现块体运动和变形的过程特征；最后，探讨相关参数对块体运动和变形规律的影响，包括爆炸距离、块间填充物的厚度和强度特征等。     

横向流动土体作用下的群桩反应性状

借助FLAC3D程序,分析了基坑开挖后土体横向流动作用下坑内群桩的反应性状。研究了两桩、四桩、五桩、六桩群桩中基桩的反应性状,并与相同位置的单桩反应进行了比较,得到了受横向流动土体作用的群桩相互作用规律:桩基连线平行于边坡布置的两桩,相互影响并不明显;而在其它情况下,前排桩对后排桩遮拦、后排桩对前排桩阻挡,均使受影响的桩基内力分布改变,桩身最大变形量减小;受周围越多、越近桩基的影响,基桩的内力和变位减少得越多。根据桩间土体的成拱特征,定性解释了群桩相互作用的机理与规律,具体工程的现场量测结果也验证了此结论。     

地铁站内烟气流动特性和消防安全

介绍了地铁站内烟气流动和控制的试验和数值研究。在三个真正地铁站内利用甲醇油池火作为燃料进行了试验，用所获得数据来验证地铁站火灾数值模型，并进一步检验其烟控系统的性能。在站内使用了制量烟气流动模型，再现了最简单条件下每个站点的试验结果，然后把结果跟其他试验条件下的试验结果进行了比较。最后，用模型预测更复杂火灾的烟气流动情况。另外，还讨论了地铁系统的有效设计和火灾安全设施的正常运作情况。通过限制内饰面材料的燃烧性能或者安装自动喷淋系统都可以有效控制热释放速率，且在站点两端开设逃生路线、站台和地铁隧道直接卷帘的正常启动等可有效保证安全疏散。     

Numerical simulations on fire spread and smoke movement in an underground car park

The Fire Dynamic Simulator code is used to investigate fire spread and smoke movement in a large underground car park under different fire scenarios. Initially, by comparing with experimental results of heat release rate of a single car fire, the development of car fire is designed by letting surface densities of the fuel over the car. Fire spread and movement of smoke are then investigated under different ventilation conditions. Simulated results show that the development of car fire in the underground car park can be classified into four stages; namely an initial stage, a developed stage, an extinction and re-burning stage and another fast-developed stage. Affected by ventilation systems, fire develops rapidly resulting in consuming most oxygen quickly followed by early extinction of the fire. After extinction of the fire, with more ambient air drawn into the car park due to ventilation, re-ignition takes place with accelerated development. In addition, detailed field distributions of temperature and velocity vectors are given. It is found that the smoke layer decent to the top of the car after 15 min and the hot smoke flows in a disorderly manner resulting in the spread of fire more rapidly.     

氧化沟混凝土池壁产生渗漏水原因分析

在介绍氧化沟池壁混凝土浇筑故障的发生及处理过程的基础上，分析了变形缝西侧池壁产生渗漏水的原因，并提出了修复处理措施，经过处理的池壁经检测未发现有渗漏水部位。     

微机在网络图中的应用

讨论微机在网络图中的应用,对网络图的时间参数结合施工进度横道图进行了计算和优化。