设置稀浆封层的水泥混凝土桥面铺装性能研究

对设置稀浆封层的水泥混凝土桥面铺装结构进行深入研究,结果表明:"水泥混凝土桥面+粘结剂+改性乳化沥青稀浆封层"为最优铺装方案。应用改性乳化沥青稀浆封层可减少投资,降低施工难度。     

Nitrogenous discharges to the eastern Gulf of Finland, the Baltic Sea: Elemental flows, stable isotope signatures, and their estuarine modification

We studied the nutrient input to the Gulf of Finland via River Neva, the largest river discharging freshwater to the Baltic Sea, and characterised the isotopic signatures (¹⁵N, ¹⁸O, ¹³C) in dissolved and particulate substances (NO₃⁻, PON, POC, DIC) in the River Neva over two seasonal cycles, as well as in samples from St. Petersburg wastewater treatment plants (NO₃⁻, NH₄⁺, PON, POC). These riverine and municipal discharges account for 40% of terrestrial inorganic N loading to the Gulf of Finland, representing annually 7% of the total nitrogen pool in the water mass of the whole Gulf. To describe and evaluate the modification of these isotopic signals along a Gulf of Finland transect towards the Baltic Proper, two cruises were arranged, one in late spring after the annual maximum in River Neva runoff, and one in autumn, in the late phase of the annual growth season.River Neva nitrate signatures of ¹⁵N and ¹⁸O indicated major agricultural fertilizer origin of nitrogen, and the isotopic composition was clearly lighter (δ¹⁵N-NO₃⁻ mean of 2.4‰ air) than previously measured from more southern rivers discharging into the Baltic Sea. Because of the light composition of the River Neva N source, close to the ¹⁵N signatures of the open Gulf, as well as of the efficient depletion of the inorganic load already in the innermost estuary, straightforward end-member tracer analysis of the transport of N in the basin is problematic. St. Petersburg wastewater ammonium showed, however, high δ¹⁵N values (ca. 13‰), which gives a first estimate of 5.8‰ for δ¹⁵N of the easternmost estuarine total inorganic N source. The available sediment data from the basin (δ¹⁵N 6 to 8‰) somewhat exceeds the average source signature. This emphasizes the significance of biological transformation processes, most importantly assimilation of inorganic nitrogen, food web interactions and denitrification, which all involve isotopic fractionation, for the mass balance models describing the dynamics of the sources and sinks of the N cycle of the basin.     

成都地铁火车南站-省体育馆站区间隧道始发段泥水盾构施工技术

采用盾构法进行富水砂卵石地层的施工，在全国尚属首次，介绍了成都地铁盾构4标始发段的掘进情况，对泥水盾构机在富水砂卵石地层中的施工技术进行了初步探讨，可供类似工程参考。     

橡胶粉改性沥青混合料稀浆封层的性能研究

对掺入不同数量的橡胶粉和纤维的稀浆封层混合料的湿轮磨耗和负荷轮粘砂指标进行了对比分析研究,提出了橡胶粉的适宜目数和用量,以及纤维的最佳添加量。研究表明加入适当数量的橡胶粉和纤维,可显著提高稀浆封层混合料的路用性能。     

低塑性砂土底基层施工工艺研究

以国道220线改扩建工程为例,针对低塑性砂性土在二灰土底基层使用时混合料强度不能满足设计要求的实际情况,研究了底基层室内不同目标配合比的试验结果和影响因素。详细介绍了现场施工技术要求和质量控制方法,采取了掺加一定比例碎石的措施,提高了混合料的强度,满足了设计要求,有效地解决了低塑性砂土在底基层中使用的难题。     

沉降性浆体管道减阻的研究进展

沉降性浆体减阻方式主要有4种:采用可溶解的高分子聚合体、采用纤维材料减阻、采用螺旋流减阻和改变管道的形状等。虽然这些减阻方式存在一些不足,但其中有些减阻措施已在沉降性浆体的输送中得到了应用。文中对各种减阻方式进行了分析和探讨。     

S259号泥水平衡盾构机改造

介绍中铁隧道股份有限公司曾用于重庆主城过江排水隧道掘进的德国海瑞克公司生产的S259号泥水平衡盾构机,改造为用于成都地铁Ⅰ号线一期工程4标试验段隧道工程的同类型盾构机的实例,改造工作仍由海瑞克公司完成。该例盾构改造的性质为同类机型的直径缩小改造。     

泥水盾构主机推进速度与泥浆系统能力的匹配

通过分析泥浆系统流量与盾构掘进进度关系,对泥水盾构主机推进速度与泥浆系统能力的匹配进行了阐述,为盾构采购用户提供一些参考。     

泥水盾构下穿侵限隧道箱涵施工技术研究

盾构施工过程中,若遇到箱涵侵限隧道且无法改迁的情况下,施工风险和难度会难以控制。以广州8号线9标出入段线下穿侵限箱涵为背景,研究箱涵处理技术。经现场分析和复测,确定箱涵与隧道之间的位置关系,通过对箱涵清理、回填、制作抗浮压板等技术,解决了箱涵侵入隧道范围导致盾构无法掘进的问题;通过提前对刀盘和刀具进行优化以及掘进过程中设置合理的掘进参数,保证了盾构快速、平稳、连续穿越箱涵。同时,利用特制的惰性砂浆作为缓冲层,可有效隔断盾尾后方水土流动,确保了后期成型隧道运营的稳定性。该技术的研究与应用,确保了盾构施工和既有结构的安全,为以后类似盾构施工也提供了借鉴和参考。     

压力灌浆在预应力锚索加固边坡中的工艺研究

根据昆石高速某边坡地质条件,采用预应力锚索加固方法,设计了锚索长度和分布形式,对锚索灌浆的施工,提出了压力灌浆新工艺,采用土工布制成的止浆袋新技术有效解决了普通止浆效果差的缺陷.边坡加固后效果证明该方法成本低,机械设备投入少,有利于大面积推广.