Assessment of seasonal sedimentation in rain-fed irrigation reservoirs by a hillslope erosion modeling approach

A distributed hillslope model is presented for the computation of seasonal sediment loads flowing into the rain-fed irrigation reservoirs （tanks） from the mountainous catchments in Sri Lanka. The model is based on the subdivision of the catchment into hillslopes and application of a sediment transport capacity equation at hillslope scale and computation of sediment loads transported to the tanks. Coarse and fine sediment loads due to hourly excess rainfall during a season are separately estimated. The model depends on fewer parameters and can be easily calibrated for a tank. The model calibration only requires measurements of coarse and fine sediment loads transported into the tank due to several rainfalls of different intensities from a representative subcatchment of the tank. Coarse sediment loads are measured by using a sediment trap installed across an ephemeral stream draining the subcatchment. Fine sediment loads are obtained by measuring the discharge and accompanied sediment concentrations over the sediment trap. The model is calibrated, verified and applied for an irrigation tank in Sri Lanka to estimate the seasonal sedimentation loads.     

基于原位试验成果的地基非线性沉降分析

提出了利用小尺寸载荷试验（PLT）及标准贯入试验（SPT）成果准确求解地基非线性沉降的新方法。首先利用压板载荷试验成果经过双曲线拟合,确定出某一土层地基土的修正切线模量;然后根据不同深度的SPT标贯击数按照线性相关关系,确定该土层不同深度各分层土的修正切线模量;最后依据分层总和法求解地基或基础的非线性沉降。该方法的特点是能进行加载至极限状态的全过程非线性沉降分析,而计算原理简单,计算参数全部来自现场原位测试,附加应力依据压板试验成果进行自动修正。分析广东某大型油罐地基及某高层建筑筏板基础的沉降结果表明,该方法计算结果准确可靠,能满足以沉降控制为目标的地基基础工程设计要求。     

冰力模型实验

本文首先简述了冰力模型实验的概况,然后介绍了在国内第一座冰池实验中进行的首次冰力模型实验——渤海辽东湾抗冰平台冰力模型实验的设备、模型冰制取技术和实验结果。实验中,冰排的破坏符合一般规律,它预示了现场冰的破坏现象;冰力值稍低于计算值,但更合理,可供设计参考;冰力谱中存在着明显的主频率,它集中于0.8HZ左右。     

油罐基础不均匀沉降主要影响因素的敏感性分析

在上部均布荷载作用下柔性基础基底压力是均匀分布的,基底以下土体在同一深度附加应力呈现中间大、周围小的分布规律,导致基础沉降中间大、周围小。刚性基础的沉降是均匀的,必然导致基底压力的分布为周围大、中间小。软基上的油罐筏板基础是具有一定刚度的基础,但并非刚性基础,因而基底压力分布应该介于柔性基础和刚性基础之间,沉降为中间大、周围小的不均匀分布。基于ABAQUS有限元分析,结合工程实际情况,采用UH模型作为土体本构模型进行了模拟分析,对筏板厚度、地基刚度等影响基础不均匀沉降的主要因素进行敏感性分析,探求变刚度地基在油罐基础不均匀沉降中的影响规律。     

立式储罐基础隔震动力反应特性分析

本文基于文献[1]建立的立式储罐基础隔震体系，针对阻尼，波高，隔震震频率等因素，进行了分析和研究，给出了工程设计所需的隔震频率、阻尼比并分析了隔震周期对波高控制的影响。     

Investigation of the dynamic behaviour of a storage tank with different foundation types focusing on the soil‐foundation‐structure interactions using centrifuge model tests

This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd.     

Application of tank,NAM, ARMA and neural network models to flood forecasting

Two lumped conceptual hydrological models, namely tank and NAM and a neural network model are applied to flood forecasting in two river basins in Thailand, the Wichianburi on the Pasak River and the Tha Wang Pha on the Nan River using the flood forecasting procedure developed in this study. The tank and NAM models were calibrated and verified and found to give similar results. The results were found to improve significantly by coupling stochastic and deterministic models (tank and NAM) for updating forecast output. The neural network (NN) model was compared with the tank and NAM models. The NN model does not require knowledge of catchment characteristics and internal hydrological processes. The training process or calibration is relatively simple and less time consuming compared with the extensive calibration effort required by the tank and NAM models. The NN model gives good forecasts based on available rainfall, evaporation and runoff data. The black‐box nature of the NN model and the need for selecting parameters based on trial and error or rule‐of‐thumb, however, characterizes its inherent weakness. The performance of the three models was evaluated statistically. Copyright © 2000 John Wiley & Sons, Ltd.     

新型桁架式Spar生产平台储油系统及总体设计

新型桁架式Spar生产平台具有15 000 t的凝析油储存能力,采用基于油水置换技术和三级油水分离工艺的新型储油系统设计,这在现役和在建的Spar平台中尚属首次。介绍了平台的总体方案,包括主要技术参数、舱室划分、空船重量重心和系泊系统等。阐述了油水置换储油系统的布置方案以及三级油水分离工艺流程。并分析了平台的主要性能,包括气隙、运动耦合、稳性。最后通过风浪流联合运动响应的水池试验,验证了平台在百年一遇的海况下具有良好的运动性能。     

立式钢制储罐基于地震损伤性能的抗震设计方法

针对立式钢制储罐在强烈地震作用下会产生不同程度的损伤的特点，遵循抗震设计规范的“小震不坏，中震可修，大震不倒”的抗震设计原则，结合三水准烈度，提出了储罐的地震损伤性能目标，并给出了基于地震损伤性能的抗震设计方法。所提出抗震设计方法，更加准确地考虑了储罐的提离问题。     

Model tank electrical resistivity characterization of LNAPL migration in a clayey-sand formation

A modeling tank time-lapse 2D electrical resistivity experiment was undertaken to model the leakage of petroleum products from underground pipelines into a clayey-sand aquifer. Numerical modeling was employed to simulate the electrode arrays that would resolve the post-leakage subsurface image most efficiently. Of the four arrays tested, the dipole–dipole array proved most effective and was adopted for the laboratory studies. Pre-injection surveys were conducted to assist in discriminating between features caused by hydrocarbon accumulation and those due to natural geologic variability. Subsequently, controlled injection of diesel–oil into the model tank was undertaken at regular intervals over a period of 3 days. Experimental evidence obtained from the studies indicates that high resistivity build up few hours after injection is directly related to hydrocarbon accumulation. Rather than biodegradation of the hydrocarbon, a more probable explanation for the observed decrease in resistivity observed a few hours after injection is simply that the hydrocarbons drained to a deeper level after pooling temporarily at a shallow level.