被动区花岗岩残积土弱化对深基坑的影响

花岗岩残积土遇水软化崩解不仅造成施工困难,也给基坑自身安全及周边环境保护带来极大风险。为了研究坑底被动区花岗岩残积土遇水软化崩解对基坑的影响,以花岗岩残积土地区某地铁车站深基坑为对象,运用PLAXIS有限元软件,系统地开展了土体弱化及弱化深度对基坑变形受力影响的有限元计算。结果表明:围护结构水平位移最大值、踢脚变形、地表沉降最大值均随着坑底土体弱化深度的增加而增大,当弱化深度较小时,上述值增长幅度较小,当弱化深度较大时,上述值急剧增大;此外,围护结构水平位移最大值位置及最大弯矩会随着土体弱化深度的增加而增大,临近坑底支撑会随土体弱化深度的增加而承担较大的转移压力。因此,在花岗岩残积土地区基坑工程施工过程中,需减少坑底土体弱化深度,避免土体大范围弱化。研究结果可为其他类似工程施工决策提供参考。     

典型滩涂环境因子对植物群落空间分布的影响

长江口滩涂生境具有较高的环境异质性,导致不同滩涂植物群落的分布特征存在显著差异。为分析长江口典型滩涂植物群与环境因子的关系,在崇明东滩和奉贤金汇港两个典型滩涂对其环境因子及植物群落特征进行了采样分析。分析结果表明,滩涂随着高程的增加,受潮汐的影响逐渐减少,环境因子呈现一定的规律性变化,滩涂植物对环境因子具有不同的适应力是导致长江口盐沼植被带状分布的重要因素。崇明东滩作为植物群落较为成熟的滩涂,芦苇和互花米草的生长表现沿高程呈"V"型。奉贤金汇港作为植物建群较短的新生带滩涂,互花米草的生长表现沿高程呈梯度分布。两区域植物群落表现不同的主要原因有可能是建群时间、演替阶段、滩涂受潮汐作用和立地条件等造成的。     

Zonal disintegration phenomenon in rock mass surrounding deep tunnels

Zonal disintegration is a typical static phenomenon of deep rock masses. It has been defined as alternating regions of fractured and relatively intact rock mass that appear around or in front of the working stope during excavation of a deep tunnel. Zonal disintegration phenomenon was successfully demonstrated in the laboratory with 3D tests on analogous gypsum models, two circular cracked zones were observed in the test. The linear Mohr-Coulomb yield criterion was used with a constitutive model that showed linear softening and ideal residual plastic to analyze the elasto-plastic field of the enclosing rock mass around a deep tunnel. The results show that tunneling causes a maximum stress zone to appear between an elastic and plastic zone in the surrounding rock. The zonal disintegration phenomenon is analyzed by considering the stress-strain state of the rock mass in the vicinity of the maximum stress zone. Creep instability failure of the rock due to the development of the plastic zone, and transfer of the maximum stress zone into the rock mass, are the cause of zonal disintegration. An analytical criterion for the critical depth at which zonal disintegration can occur is derived. This depth depends mainly on the character and stress concentration coefficient of the rock mass.     

改进生物地理学优化算法在配电网无功优化中的应用

针对生物地理学算法(BBO)信息利用能力强但搜索能力不强的问题,提出了一种结合遗传算法改进变异操作的算法.改进算法充分利用了遗传算法的搜索能力,使算法的寻优能力得到了很大的改善.将该算法应用于IEEE34节点的系统,采用分区的方法进行无功补偿优化.算例表明:与基本BBO算法、遗传算法的无功优化相比,改进算法在计算速度和优化效果方面都具有明显的优势.     

自然通风的设计策略及模拟分析

介绍了自然通风的设计策略，阐述了采用网络法、计算流体力学(CFD)及区域模型法(Zonal odel)对自然通风的模拟分析，说明了CFD中直接数值模拟(DNS)、雷诺平均纳维尔一斯托克斯方程(RANS)、大涡模拟(LES)这三种形式的特点，最后提出了自然通风的设计策略选择和模拟分析中应注意的几个问题。     

一起因电流互感器二次铁心工艺质量不良引发色谱异常分析

例行油色谱试验发现同一批次多台220 k V电流互感器中氢气及总烃含量超标。经返厂试验和解体检查,认为二次铁心选材及工艺处理不良,是造成色谱异常的主要原因[1]。     

岩体间隔破裂机制及演化规律初探

 在地壳岩层或岩土工程结构中,有一个非常重要的破裂现象,即间隔破裂现象,其形成机制到目前仍不十分清楚。这些现象包括地层中的等间距破裂、大地干裂(龟裂)以及深部巷道围岩中的间隔破裂(分区破裂)等。此外,混凝土结构中的间隔裂纹、陶瓷表面因冷缩产生的龟裂等,都是间隔破裂现象的典型例子。以此为背景,介绍通过RFPA数值试验方法研究间隔破裂机制和演化规律的初步结果,包括：(1) 条状间隔破裂(平行破裂);(2) 网状间隔破裂(龟裂);(3) 环状间隔破裂(分区破裂)。     

复杂地质条件下双联拱隧道主要施工技术

以石板桥双联拱隧道为例,阐述了主要施工技术在隧道施工中的研究内容,介绍了锚索、抗滑桩、钢花管注浆技术在隧道边仰坡处理中的应用,大管棚、小管棚在隧道超前支护中的应用,分区防水在隧道防水中的应用.     

地震诱发高速黄土滑坡的机理研究

针对１９２０ 年海原大地震（ Ｍｓ ＝ ８ ．５） ,１７１８ 年通渭大地震（ Ｍｓ ＝ ７ ．５） 和１６５４ 年天水大地震（ Ｍｓ ＝ ８ ．０） 等诱发的高速黄土滑坡所出现的种种现象与特征,提出了一种地震诱发高速黄土滑坡的机理---黄土体解体、斜抛和粉尘化效应。通过动力变形分析导出了黄土滑体斜抛运动的全过程及滑速、滑距公式。以海原大地震时,西吉县（１０°区） 回回川高速黄土滑坡为例,对这些公式进行验证,结果与实际情况相符。     

“Nata Puree,” a Novel Food Material for Upgrading Vegetable Powders,Made by Bacterial Cellulose Gel Disintegration in the Presence of (1,3)(1,4)-β-Glucan

Pulverization is a potentially powerful solution for the resource management of surplus- and non-standard agricultural products, maintaining their nutritional values for long and ensuring their homogeneity, whereas their original textures could disappear to narrow the application ranges. Therefore, new technologies should be developed for reconstructing the powders to provide them with new physical characteristics. Herein, we developed a novel food material, nata puree (NP), by nata de coco (bacterial cellulose gel) disintegration with a water-soluble polysaccharide using a household blender. The process worked well with (1,3)(1,4)-β-glucan (BGL) as the polysaccharide, which could be substituted with barley extract. Lichenase treatment of the NP dramatically modified its physical properties, suggesting the importance of the BGL polymeric forms. NP exhibited distinct potato powder and starch binding activities, which would be attributed to its interactions with the cell wall components and a physical capture of powders by the NP network, respectively. NP supplementation into the potato paste improved its firmness and enabled its printable range shift for 3D food printing to a lower powder-concentration. NP also promoted the dispersion of powders in its suspension, and designed gelation could also be successfully performed by the laser irradiation of an NP suspension containing dispersed curdlan and turmeric powders. Therefore, NP could be applied as a powder modifier to a wide range of products in both conventional cooking, food manufacturing, and next generation processes such as 3D food printing.