斜坡地基上高填方路堤极限承载力研究

结合山区高速公路建设的实践,采用大型室内模型试验,找出了荷载作用下斜坡地基上高填方路堤滑动破坏面出现的位置及形态,并确定了其极限承载力的大小。在通用条分法的理论基础上运用Visual Basic编程语言编制了斜坡地基上填方路堤极限承载力计算程序,并应用于该试验模型的计算分析,计算与试验结果的对比分析表明,利用极限平衡通用条分法不仅简单可行,且具有较高的计算精度。     

四排局部冻结法在上海地铁修复工程中的应用

上海地铁某修复工程,在完好隧道与破坏隧道连接段采用冻结法施工垂直封水挡土止水墙,取得圆满成功。利用现场监测数据,判别了冻结管是否漏盐水以及隧道内是否充填密实,得出了冻土壁温度场形成规律,计算出积极冻结期结束时间。在浦东隧道清淤排水、浇筑混凝土止水墙阶段,分析了各施工工序对冻土墙温度影响。分析结果表明,冻结法施工质量的好坏可由温度反映出来。通过合理布置温度监测点,采用信息化施工,掌握温度变化规律,可确保复杂工程冻结施工安全。     

某些矿物中同心层状鲕(豆)粒的自组织成因

本文首先综述了矿物中同心层状鲕(豆)粒的基本特征,接着提出该鲕状结构的二阶段成因模式(早期胶团从沉积物中的快速形成和晚期胶团在自催化反馈机制的作用下的有序化)。最后,用自组织(耗散结掏) 理论和动力学分析方法揭示出如下结论:①自催化反馈机理是胶团中杂质元素的催化结晶;②胶团在有序化过程中能形成时-空有序的自组织结构即鲕粒同心层;③胶团中凝胶浓度和杂质元素浓度在相空间内为一极限环,定态胶团失稳后将沿着极限环闭轨演化并最终形成同心层状矿物鲕粒。寻找有序结构和自反馈机制是研究自组织结构的有效方法     

用有限区域风速场准确求解流函数和速度势场的方法

流函数和速度势是气象业务和研究中常用于表述风速的一组变量。用有限区域风速场, 使用有限差分方法求解得到的流函数和速度势场重建初始风速场, 由于受区域边界的限制往往有明显的偏差。虽然有许多求解方法的研究, 但是, 至今仍尚未见到一种真正准确的求解计算方案。首先, 介绍用Arakawa A网格和D网格分布的有限区域风速场求解流函数和速度势场的一般有限差分计算方法, 探讨用它们的解重建风速场产生误差的原因。然后, 针对这些原因, 对给定的有限区域, 通过线性外推初始风速场, 扩展求解计算区域, 使用协调、一致的有限差分格式方案, 准确计算求解区域的边界有旋风速、散度风速和速度势的定解边界条件, 以及恰当选择流函数、速度势、涡度和散度等变量的分布网格, 设计了用上述两种网格分布的风速场准确求解流函数、速度势场的方案, 并对其正确性加以证明, 它们可以推广应用于其他Arakawa网格。用实际资料试验同样显示, 方案避免了重建风速场误差的出现, 与初始风速场相比, 全场风速最大偏差精度达到10-12m/s或以上, 在计算机精度造成的计算误差影响范围内。本文的研究很好解决了长期以来用有限区域风速场、 使用有限差分方法无法准确求解流函数和速度势场的问题。     

有限区域细网格模式产品在江汉平原暴雨预报中的应用

利用湖北省提供的有限区域细网格模式数值预报产品及降水实况资料，用逐步回归法拟合出江汉平原等区域暴雨方程。方程的拟合效果比较理想，此方程尚有待台站业务考核及改进。     

三维地下水流中常规观测孔水位的形成机理及确定方法

对地下水三维流中常规观测孔中水位的传统计算方法提出质疑, 认为计算观测孔中水位的Hantush Бочевер方程是缺乏物理基础的纯数学方法.分析了形成观测孔中水位的机理, 提出三维地下水流中常规观测孔中只是孔口的流量为零, 而孔内却存在"抽水"和"注水"的井孔; 多层井(multilayerwell) 不一定要求"多层"的条件, 在均质单一含水层中的井孔可以具有多层井的基本特征; 混合井孔的水位并不"混合", 混合观测孔中存在符合机理的水头分布和流量分布规律等观点.普遍而言, 三维流中的观测孔不能用通常所说的线汇/线源刻画, 也不能用近几年提出的孔内为层流(线性流) 的假定来研究该问题, 然而可用笔者于1993年提出的"渗流-管流耦合模型"和"等效渗透系数"方便、有效地模拟.就说明性算例而言, Hantush Бочевер方程只能近似用于孔径大于0.2m且径距大于10~20m的条件.      

IMPACT OF HUMIDITY DATA ON THE PREDICTION OF ONSET VORTEX WITH A LIMITED AREA MODEL

A limited area model has been applied to study the impact of satellite-derived relative humidity data on the predic-tion of onset vortex of monsoon 1979.The results show that inclusion of satellite-derived relative humidity data im-proved the prediction of track of the cyclonic circulation and the rainfall rates in the region of the vortex.     

Influence of wavelength on the parameterization of drag coefficient and surface roughness

Surface waves are the roughness element of the ocean surface, the air-sea interaction processes are influenced by the wave conditions. The dynamic influence of surface waves decays exponentially with distance from the air-water interface. The relevant length scale characterizing the decay rate is the wavelength. The parameterization of drag coefficient and surface roughness can be significantly improved by using wavelength as the reference length scale of atmospheric measurements. The wavelength scaling of drag coefficient and dynamic roughness also receives support from theoretical studies of wind and wave coupling.     

Multi‐model ensemble prediction of terrestrial evapotranspiration across north China using Bayesian model averaging

Using high‐quality dataset from 12 flux towers in north China, the performance of four evapotranspiration (ET) models and the multi‐model ensemble approaches including the simple averaging (SA) and Bayesian model average (BMA) were systematically evaluated in this study. The four models were the single‐layer Penman–Monteith (P–M) model, the two‐layer Shuttleworthe–Wallace (S–W) model, the advection–aridity (A–A) model, and a modified Priestley–Taylor (PT‐JPL). Based on the mean value of Taylor skill (S) and the regression slope between measured and simulated ET values across all sites, the order of overall performance of the individual models from the best to the worst were: S–W (0.88, 0.87), PT‐JPL (0.80, 1.17), P–M (0.63, 1.73) and A–A (0.60, 1.68) [statistics stated as (Taylor skill, regression slope)]. Here, all models used the same values of parameters, LAI and fractional vegetation cover as well as the forcing meteorological data. Thus, the differences in model performance were mainly attributed to errors in model structure. To the ensemble approach, the BMA method has the advantage of generating more skillful and reliable predictions than the SA scheme. However, successful implementation of BMA requires accurate estimates of its parameters, and some degradation in performance were observed when the BMA parameters generated from the training period were used for the validation period. Thus, it is necessary to explore the seasonal variations of the BMA parameters according the different growth stages. Finally, the optimal conditional density function of half‐hourly ET approximated well by the double‐exponential distribution. Copyright © 2016 John Wiley & Sons, Ltd.     

平度市国土资源局全面推进“双保”行动的探索

为应对国际金融危机,平度市国土资源局积极响应国土资源部在全国范围内部署开展的＂保增长、保红线＂双保行动,立足部门职能,扎实工作,加强和改善土地宏观调控新机制,有效保障扩大内需,保障重点项目用地,促进经济平稳较快发展。