本文提出了一种针对海上风电单桩基础结构计算的改进竖向地基梁法,并对单桩基础结构进行了优化计算.对单桩基础结构采用竖向地基梁法计算,基于m法计算土抗力,限制浅层土抗力的极限值不能超过极限土压力.结合工程情况,利用传统竖向地基梁法与改进方法,对单桩基础结构进行了优化计算,两种方法的计算结果存在一定差异,改进计算方法所得最大泥面水平位移增大34.6％.对于变形控制较为严格的海上风电桩基础结构,限制浅层土抗力的极限值不能超过极限土压力并使用改进方法对单桩结构进行计算是必要的.

In order to improve the evaluation ability of bearing capacity of offshore large-diameter monopile, the initial high strain detection and repeated high strain detection with an interval of 10-84 days were carried out on 6 large-diameter monopiles with a diameter of 7.2m-7.4m in the offshore wind field dominated by cohesive soil layer. The results show that the time-dependent increase of tip resistance, pile side resistance and total resistance of large-diameter monopiles in the same offshore wind farm has great discreteness, and the axial force increment of pile has a consistent change trend. This paper puts forward the prediction interval of 95% guarantee rate of bearing capacity increment of offshore large-diameter single pile based on depth, which provides a basis for the design of large-diameter monopile.

Combined action of external sulfate attack (ESA) and cyclic wetting–drying (CWD) results in the severe durability issue of cement-based materials. A comprehensive microstructural investigation of deterioration mechanism of mortar exposed to ESA and CWD is scarce until now. By means of multiple techniques, the phase evolution, microstructural evolution, pore structure variation and thus the deterioration mechanism of mortars with different water-to-cement ratios (0.3 and 0.5) exposed to ESA and CWD, are investigated in this study. It is found that the amount of portlandite declines fast at the first two wetting–drying cycles and decrease gently in the following cycles, the loss of OH− into external sulfate solution plays a dominant role over uptake of Na+ from external sulfate solution during combined action of ESA and CWD; the evolution of pore size distributions of mortars with different water-to-cement ratios exhibit distinct patterns; decalcification of CSH leads to the shrinkage of CSH and collapse of interlayer space and gel pore, responsible for the decreasing amount of interlayer/gel pore at the first 10 wetting–drying cycles and the increase of the amount of interlayer/gel pore at the following 8 cycles; only a few gypsum and thenardite/mirabilite are detected, ettringite is the principal cause of deterioration of mortar subject to ESA and CWD.

在天津市滨海新区汉沽地区进行双套管成孔植入竹节桩的沉桩试验.通过计算完成了振动锤的选型,通过采用双套管工艺成孔,合理安排植桩及灌浆工序,证实了双套管成孔植桩工艺的可行性和优越性.

在天津市滨海新区某典型场地,分别进行了长螺旋钻孔植桩和锤击法施工的竹节桩单桩抗压承载力试验,并与锤击法施工的PHC管桩进行对比,对不同施工工艺的承载力特点进行了分析.现场试桩数据表明,锤击法施工的竹节桩的承载力大于锤击法施工的PHC管桩,但离散性大,适用性差.长螺旋钻孔植桩工法竹节桩的承载力比锤击法施工PHC管桩承载力提升明显,且和锤击法施工的竹节桩比,其承载力发挥相对稳定.

面对我国海上风电开发的重大需求及施工装备技术性能的严重不足,从工程实际需求出发,充分吸收国内外自升式平台优点,并综合考虑我国沿海地质与海况等条件,研制我国新一代海上风电安装船"港航平9".介绍该平台的总体布置及参数、关键设备的设计思想和方案,总结其设计特点,并对该平台的施工工艺进行说明.通过工程实践检验,"港航平9"施工实用性强,所形成的工艺施工质量满足工程项目要求,施工安全性及效率相比传统方式有较大提高,成本也相对较低.

以某新建地铁盾构区间下穿既有地铁明挖区间结构施工为例,为研究盾构施工对既有区间的影响,建立三维有限元模型进行了模拟计算,模拟计算中考虑了施工中的开挖、施加掌子面及施作管片过程,计算结果表明盾构施工不会影响既有地铁区间结构的正常使用及运营.

文章针对新建地铁暗挖区间下穿既有铁路框构桥的施工过程，采用三维有限元模型进行了模拟计算。模型中考虑了双线区间施工影响及管棚初期支护的作用。通过模拟计算表明，下穿施工不会影响铁路框构桥的正常使用。

The invention relates to a precast concrete jacket type offshore wind turbine foundation. The offshore wind turbine foundation is characterized by comprising an reinforced concrete frame precast ashore, foundation piles and a cap beam, wherein the reinforced concrete frame precast ashore comprises upper and lower guide beams, a connecting beam, stand columns and a core tube; reserved pile holes are evenly distributed in the upper and lower guide beams; the foundation piles penetrate through the reserved pile holes; a plurality of stand columns are evenly distributed between the upper and lower guide beams; a cylindrical core tube is arranged in the center of the upper and lower guide beams; the core tube is connected with the upper and lower guide beams through the radial connecting beam to form an integral structure; the cap beam is arranged on the surface of the upper guide beam; and the cap beam, the reinforced concrete frame and the foundation piles form an integral precast concrete foundation structure. The precast concrete jacket type offshore wind turbine foundation has the benefits as follows: a traditional practice that offshore gravity type foundations adopt conventional cast-in-place concrete foundations is changed, the lighter reinforced concrete structure frame is precast ashore firstly and then placed at the seabed of a coastline, and precast foundation piles are inserted into and fixedly connected with the frame to form the integral foundation, and the integral wind turbine foundation which is firm and resistant to wind waves can be built.

The concrete temperature stress is calculated to study the effect of the macro-heterogeneity using the commercial FEM software.Parameters,such as the elastic modulus of concrete,hydration heat of cement and the concrete tensile strength which changes with age,are considered,except the creep of concrete at early ages.The results show that the tensile strength of concrete is the lowest of components and the thermal cracking seems to become earlier when there is macro-heterogeneity in the concrete.

Presuming the material parameters’fluctuation obeys normal distribution in finite interval caused by the macro-heterogeneity of concretet,he finite elements are assigned material properties individually to calculate the thermal stress of concrete in order to examine the impact of heterogeneity of concrete.The results show that the thermal stress' variation increases with the material parameters' fluctuation increasing.The effects of different parameters' fluctuations are different.The coefficient of thermal expansion has the greatest effect among the parameters considered.