南宁地区富水圆砾层袖阀管注浆加固技术

为了解决南宁地区富水圆砾地层袖阀管注浆加固过程中浆液扩散难以控制、加固效果难以保证的问题,通过室内试验和现场实践,从工艺参数、浆液配合比等方面进行优化改进,总结得出在制浆过程中,通过添加外掺料形成能提高浆液抗分散能力的复合浆液,并采取低压慢注相结合的注浆新工艺,从而提高富水圆砾层注浆加固的可靠性。     

二维边界层流动转捩过程的数值计算(英文)

As a basic problem in many engineering applications, transition from laminar to turbulence still remains a difficult problem in computational fluid dynamics(CFD). A numerical study of one transitional flow in two-dimensional is conducted by Reynolds averaged numerical simulation(RANS) in this paper. Turbulence model plays a significant role in the complex flows' simulation, and four advanced turbulence models are evaluated. Numerical solution of frictional resistance coefficient is compared with the measured one in the transitional zone, which indicates that Wilcox(2006) k-ω model with correction is the best candidate. Comparisons of numerical and analytical solutions for dimensionless velocity show that averaged streamwise dimensionless velocity profiles correct the shape rapidly in transitional region. Furthermore, turbulence quantities such as turbulence kinetic energy, eddy viscosity, and Reynolds stress are also studied, which are helpful to learn the transition's behavior.     

Numerical investigation of mooring line damping and the drag coefficients of studless chain links

The chain/wire rope/chain combination is a commonchoice for mooring offshore floating platforms. However, data ofthe drag coefficients of chain links are rather limited, resulting inuncertainties with the calculations of the drag force, and hence thedamping of the mooring system. In this paper, the importance of theselection of the drag coefficient is first investigated. Thecomputational fluid dynamics （CFD） method is then used todetermine the drag coefficients of a studless chain under steadyflows. Numerical model validation is first completed by simulatinga smooth circular cylinder under steady flows. In particular, theperformance of different turbulence models is assessed through thecomparisons between the calculations and the experimental results.The large eddy simulation （LES） model is finally selected for thesimulation of steady flows past a chain. The effects of the Reynoldsnumber on the drag coefficient of a stud-less chain is also studied.The results show that the calculated drag coefficients of a stud-lesschain are fairly consistent with the available experimental data.     

特种减摇装置的升力模型优化

减摇鳍是一种特种减摇装置,它在船舶减摇装置中占有重要地位,本文首先对低航速减摇鳍在水中运动所受的作用力进行分析。其次,利用计算流体力学仿真软件Fluent对减摇鳍在低航速状况下进行仿真分析,并利用Matlab拟合出低航速减摇鳍的动态升力模型。最后,对拟合出的动态升力公式进行验证。结果分析表明:拟合出的动态升力公式可以很好的反应减摇鳍在低航速海况下进行主动拍击过程所产生的升力,可以为舰船在低航速海况下设计减摇控制系统提供一定的参考。     

低温条件下在役管道不停输沉降的设计与施工

管道沉降施工过程中,管道暴露在大气环境中,如果昼夜温差过大,会在管道内产生轴向应力,威胁管道安全。文中以涩宁兰一线和涩宁兰二线沉降施工为例,介绍了在役管道低温条件下不停输沉降的受力计算方法、施工步骤及注意事项,并通过增加沉管过渡段长度、降低管道操作压力等措施,降低了管道沉管施工的轴向拉伸应力,确保了低温条件下管道沉降施工安全,使沉管施工安全、顺利实施。     

低标号沥青混合料的路用性能

对低标号沥青、70号普通道路石油沥青和SBS改性沥青进行了沥青混合料性能试验,并对试验结果进行了对比分析.结果表明,三种不同类型的低标号沥青混合料均满足高温动稳定度、水稳定性、冻融劈裂以及低温抗裂性能的规范要求,其中低标号沥青混合料的高温稳定性能还与SBS改性沥青较为接近.并根据试验结果确定了低标号沥青的适用区域和层位,为低标号沥青的推广和运用提供了科学依据.     

公路工程招标合理低价法投标体会

为争取较高的中标机会,招标企业应加强对以往投标工作经验教训的总结分析,认真细致地研究招标文件,掌握投标项目的实际情况和所面临的形势。结合我国某公路工程"合理低价法"招标项目投标方式,介绍其投标报价的应对思路和分析决策方法。     

公路工程招标合理低价法评标的改进方法

现行的公路工程招标合理低价法评标中存在一些问题,分析合理低价法评标中存在的投标人质量下降、围标串标时有发生、工程造价计算不准确等不合理现象,并从资格预审审查、开标评标方法、投标限价、重新招标条件、业绩公示、信用评价、分包要求等方面提出具体的改进措施,为公路工程招标提供借鉴。     

Domix与SBS改性沥青混合料性能对比研究

通过添加不同剂量的Domix沥青混合料与4.5%SBS改性沥青混合料性能对比后发现,Domix沥青混合料动稳定度高,且随试验温度的提高,沥青混合料的抗车辙性能衰减很小;运用低温弯曲破坏应变不能很好地表征Domix沥青混合料的低温抗裂性能,提出弯曲应变能密度可以很好地评价Domix沥青混合料的低温抗裂性能;Domix沥青混合料水稳定性能满足规范要求。     

青银高速公路病害段路堤土特征及原因分析

以青银高速公路K557＋000～K557＋710段路基病害为背景,结合勘察试验数据,分析了该路段的路基土的工程地质特征及病害产生原因,并计算了该段路基的稳定性及地基沉降量。