水泥搅拌桩复合地基体系在软土地基处理中的应用

文章基于土工格栅、土工格室、深层水泥搅拌桩的作用机理,以广西玉林至铁山港高速公路软土地基施工为例,介绍了土工合成材料与水泥搅拌桩组成的复合体系的设计方案,提出了该复合体系处理软土地基的施工工艺与质量检验方法。     

碾压贫混凝土基层配合比设计研究

京珠高速公路广韶扩建工程水泥混凝土路面基层采用贫混凝土基层结构,为提高工效,决定采用碾压工艺施工,但碾压贫混凝土基层在国内应用较少,现行规范找不到依据。根据施工需要,对碾压贫混凝土基层配合比设计进行了探索,首次采用RA法评价碾压贫混凝土基层的工作性,为该工程大面积施工提供合适的施工配合比。该成果的应用,对现行施工规范是一个补充,可推广使用。     

经验模式分解方法在水下目标分类中的应用

针对经验模式分解在水下目标辐射噪声分析时存在的模式混叠问题,提出基于二进滤波的经验模式分解方法,研究了水下目标辐射噪声的分解和特征提取。仿真实验表明,基于二进滤波的经验模式分解方法能很好地抑制模式混叠。最后将该方法应用于海试数据分析,处理结果与直接利用经验模式分解方法相比,识别概率提高了6%,得到比较满意的分类结果。     

水泥土搅拌桩在城市道路软土地基的应用

简要分析了软土地基的特点和危害,并介绍了软土地基处置的原则及必要性;基于实际工程案例,研究了水泥土搅拌桩在城市道路软土地基中的运用效果,并分别计算和分析了3种设定工况下不同路堤填土高度的路基工后沉降值（路中）以及工后沉降规律。通过总结发现：在一定条件下,与普通水泥土搅拌桩复合地基处理方法相比,长桩+短桩形式的水泥土搅拌桩复合地基处理方法更为有效,它不仅能提高地基承载能力,而且能减小路基工后沉降,压缩工期,取得预期效果。     

深层水泥搅拌桩在北仑港区的应用

通过北仑港区二期１＾＃、２＾＃泊位煤炭堆场南延工程实例,阐述了深层水泥搅拌桩的作用机理、施工工艺、工程检验以及应用深层水泥搅拌桩加固软土地基的优点。     

浅议水泥搅拌桩在高速公路软基处理中的应用

实例表明,水泥搅拌桩应用于高速公路软基处理时,须重视几个关键性参数的择取及直接影响软基处理效果的几点重要关系.     

Formation of Denmark Strait overflow water and its hydro-chemical composition

The dense overflow across the Denmark Strait is investigated with hydrographic and hydro-chemical data and the water mass composition of the Denmark Strait Overflow Water (DSOW) is determined by multivariate analysis. Hydrographical properties, the transient tracers CFC-11 and CFC-12, oxygen and nutrients are utilized for the water mass definitions. Distribution and characteristics of water masses north of Denmark Strait are described, the important water masses at the sill and the variability on weekly time-scales are discussed, and the entrainment and mixing of water into the overflow plume in the northern Irminger Basin is calculated. The analysis indicates that water masses both from the Nordic Seas and the Arctic Ocean are important for the formation of DSOW. It is found that water masses transported with the East Greenland Current make up about 75% of the overflow at the sill. The overflow at, and shortly south of, the sill is inhomogeneous with a low-salinity component dominated by Polar Intermediate Water. The high-salinity component of the overflow is mainly of Arctic origin. The water mass composition, and the short-term variability for 7 repeats of sections close to the sill are described, and these illustrate that the overflow is in fact a composite of a number of water masses with different formation and transport histories. This indicate that the overflow is a robust feature, but that it responds to variations in the circulation or atmospheric forcing that influences the formation of intermediate and deep water masses within the Arctic Mediterranean and the North Atlantic. At a section about 400 km south of the sill the overflow is well mixed and modified by entrainment of, mainly, Iceland–Scotland Overflow Water and Labrador Sea Water, together constituting 30% of the overflow plume. The entrainment of Middle Irminger Water dominates shortly downstream of the sill, before the overflow plume reaches too deep but the entrainment seems to be intermittent in time.     

高原多年冻土区隧道湿喷混凝土施工技术

在青藏铁路昆仑山隧道成功使用湿喷混凝土作为临时支护。通过试验和经济比选确定选用A类防冻剂、D′类速凝剂和聚丙烯纤维材料,确定水泥与骨料的比为1∶3 4,水泥用量在470kg·m-3～480kg·m-3之间,砂率为60%;水灰比为0 42～0 47。在高原缺氧环境下使用适用于低温环境的喷射机械,采取温控措施,确保喷射时拌和物温度不低于10℃,加强检查,可以保证高原冻土隧道混凝土喷射质量。     

200 MPa级活性粉末混凝土试验研究

根据加拿大舍布鲁克人行桥采用的活性粉末混凝土配制,研制了适合我国原材料的200MPa级活性粉末混凝土,抗压强度为168.6MPa,抗折强度为21.6MPa。该活性粉末混凝土具有优越的力学性能和耐久性能。由该材料制备的桥梁人行道构件已通过铁道部专家鉴定,拟用于青藏铁路桥梁的实际工程中。     

注浆加固块石堆积体在野三关隧道中的应用

以宜万铁路野三关隧道DK124+602大型富水溶腔的注浆加固为例,从注浆加固的方案制定到注浆材料的选择、配合比的选定、注浆压力的选择及注浆效果评定等方面详细介绍了溶腔体的注浆原理和过程,为类似工程的施工提供了宝贵的经验。