岩溶地质场地上某工程的桩基选型和施工

某工程位于岩溶较为发育的场地,地质情况较为复杂。根据场地具体岩土地质情况,并结合工程本身特点,分别确定采用筏板基础和桩基础。对于桩基础,通过各种工艺对比,选择冲孔灌注桩施工工艺,在施工过程中加强管理,采取多种质量保证措施,最终取得了良好的效果,为同类工程提供了经验。     

软土地区排桩式支护基坑事故分析及质量控 制简

随着城市建设的迅猛发展,限于土地资源,对地下空间的开发利用程度越来越高.地下商场、地下停车、地铁车站、高层建筑深基坑成为城市建设重大风险源之一.本文通过2起基坑事故分析,提出排桩式基坑支护质量控制要点和对策.     

建筑施工生活区节电设计及安全用电管 理简

从建筑工程施工工地临建生活区用电角度出发,着重介绍如何节约高效使用电能以及如何进行安全用电管理,并就此提出相应的措施,保证现场工作人员的安全.     

浅谈大吨位堆载静载荷沉降变形检测的一点体 会简

上海软土地区采用堆载平台反力装置对大吨位灌注桩进行静载荷检测,在无法完全满足相关规范中关于试桩中心、基准桩中心、压重平台支墩边三者的距离要求时,对基桩沉降量的测读方法进行探索和比对,为更好地控制灌注桩静载荷测试质量,提出笔者自己的见解.     

民国时期南京、武汉、重庆三座城市的历史文化内涵与建筑个性的比较分析(上)

民国时期先后作为首都和陪都的南京、武汉、重庆,同属长江流域,具有类似的地理环境,其时兴建的民国建筑,开创了我国传统建筑吸收西方技术开展城市设计的先河。三地又依城市所处环境不同而保持了各自的地域建筑特色,这为当下提供了有益的借鉴:既要传承历史,又要合理吸收西方先进设计理念,同时兼顾自然地理环境和市场需求,以建设具有中国特色的城市文化。     

Experimental study on the solvent regeneration of a CO2‐loaded MEA solution using single and hybrid solid acid catalysts

The performance of a hybrid solid acid catalyst consisting of a physical mixture of γ‐Al₂O₃ and H‐ZSM‐5 in terms of the rate and heat duty for solvent regeneration (i.e., CO₂ stripping) of a CO₂‐rich MEA solution was compared with the individual performance of γ‐Al₂O₃, H‐ZSM‐5, and H‐Y solid acid catalysts using MEA (2–7 mol/L), with initial CO₂ loading of 0.5 mol CO₂/mol MEA at 378 K. It was observed that any catalyst significantly decreased the energy required for CO₂ regeneration. The performance of the catalysts investigated ranked as follows: γ‐Al₂O₃/H‐ZSM‐5 = 2/1 > γ‐Al₂O₃ > H‐ZSM‐5 > H‐Y if the process is in the lean CO₂ loading region whereas it was H‐ZSM‐5 > γ‐Al₂O₃/H‐ZSM‐5 = 2/1 > γ‐Al₂O₃ > H‐Y if the process is in the rich CO₂ loading region. These results highlight the joint dependence on Brønsted/Lewis acidity and mesopore surface area of heat duty for solvent regeneration. © 2015 American Institute of Chemical Engineers AIChE J, 62: 753–765, 2016     

影响降膜蒸发器关键设计参数的因素分析

降膜蒸发器是一种高效并被广泛应用的关键设备。介绍了蒸发器的设计计算逻辑及数学模型,分别计算了系统压力、单管液体流量、强制循环量以及管径管长对蒸发器设计的影响,并对分析结果进行分析和比较,得出系统压力是影响蒸发器规模的主要因素。提高系统压力可大幅度降低蒸发器规模,降低投资成本。在保证蒸发器最低液体流量前提下,选用较低的单管液体流量和较大的强制循环比可以提高系统的稳定性能。     

Method for evaluating the reliability of compressor impeller of turbocharger for vehicle application in plateau area

As turbocharging diesel engines for vehicle application are applied in plateau area, the environmental adaptability of engines has drawn more attention. For the environmental adaptability problem of turbocharging diesel engines for vehicle application, the present studies almost focus on the optimization of performance match between turbocharger and engine, and the reliability problem of turbocharger is almost ignored. The reliability problem of compressor impeller of turbocharger for vehicle application when diesel engines operate in plateau area is studied. Firstly, the rule that the rotational speed of turbocharger changes with the altitude height is presented, and the potential failure modes of compressor impeller are analyzed. Then, the failure behavior models of compressor impeller are built, and the reliability models of compressor impeller operating in plateau area are developed. Finally, the rule that the reliability of compressor impeller changes with the altitude height is studied, the measurements for improving the reliability of the compressor impellers of turbocharger operating in plateau area are given. The results indicate that when the operating speed of diesel engine is certain, the rotational speed of turbocharger increases with the increase of altitude height, and the failure risk of compressor impeller with the failure modes of hub fatigue and blade resonance increases. The reliability of compressor impeller decreases with the increase of altitude height, and it also decreases as the increase of number of the mission profile cycle of engine. The method proposed can not only be used to evaluating the reliability of compressor impeller when diesel engines operate in plateau area but also be applied to direct the structural optimization of compressor impeller.     

新型人字形组合板式换热器及导流区的数值模拟

基于计算流体动力学(Computational fluid dynamics,CFD)方法,运用SOLIDWORKS三维建模软件和FLUENT软件对一种新型人字形组合板式换热器及四种新型导流区进行研究。分析了不同设计参数的新型人字形组合板式换热器换热系数和压降,得到优化后的设计参数;从流型、压降、出口流体均匀分配程度等方面对市面上常见的2种导流区进行分析,在此基础上提出4种新型导流区,通过数值模拟研究其导流效果。结果发现:新型人字形组合板式换热器J型板较市面上常见的M型板的综合性能更优。当组合板中大波纹倾角板片(②板片)的倾角为60°,波纹截距为18 mm、16 mm或者14 mm中某一值时,随着组合板中小波纹倾角板片(①板片)波纹倾角增大,无论是冷流体还是热流体,表面传热系数和压降均增大。当①板片的波纹倾角为30°或40°,②板片的波纹截距变化对组合板片的性能影响不大;当1板片的波纹倾角为50°,②板片的波纹截距变化对组合板片的性能影响较大。导流区的设计对流体分布情况起主要影响作用。市面上常见的某种常规型导流区导流效果差,压降大,某公司M系列巧克力块型的导流区导流效果较好,压降小。4种新型导流区比常规型导流区的导流效果更好,压降介于常规型和巧克力块型之间,其中新型导流区Ⅲ的导流效果最好,压降很小。     

Estimating the flow velocity and discharge of ADCP unmeasured area in tidal reach

Due to the ringing and side-lobe interference, acoustic Doppler current profiler (ADCP) is unable to accurately capture the complete velocity profile in open channels near the water surface and channel bottom, which are usually called unmeasured areas. At present, the flow velocities through the unmeasured areas are most commonly estimated using the power law with the power set to be the default value. However, since the flows are unsteady and nonuniform in tidal reaches, the velocity distribution model and corresponding parameters will vary with the bathymetric, tide period, etc. Therefore, the most common estimation with the power law may not be suitable in tidal reaches. In this paper, a simple determination method of the best model is proposed. Firstly, the parameters in three classical velocity distribution models, which are called power law, logarithmic law and parabolic law models, are solved by least squares based on the ADCP measured velocity cells. Then, the corresponding root-mean-square error (RMSE) of each model is used for the quantitative indicator that the model with the minimum RMSE is chosen as the best model. At last, the flow velocity and discharge of the unmeasured area are estimated by the best model. The experiments carried out in the tidal reach of Yangtze Estuary showed that vertical flow velocity distribution various with the bathymetry and tide period, and the best models averagely improved about 2.0% of the relative standard deviation (RSD) relative to the power law method in the discharge estimation, especially at some tide period the RSD of the best model was several times better than that of power law model. For Yangtze River with an annual average discharge of 3.0×10⁴ m³/s, the improvement should not be ignored. Therefore, it will be necessary to use the best model with minimum RMSE to estimate the flow velocity in tidal reach.