图G的零阶广义Randi?指数表示为R0α(G)=∑v∈Vdα(v),其中α是实数,d(v)是点v的度.本文基于零阶广义Randi?指数分别给出了围长g ≥ 5、δ ≥ 2的图是λ2最优及g ≥ 6、δ≥2的图是λ3最优的充分条件.
In order to recycle construction waste and waste tires as resources, self-compacting rubber recycled concrete was prepared with different amounts of recycled coarse aggregate and rubber particles. The working performance and mechanical properties of self-compacting concrete under different substitution ratios of the two materials were studied, and its mechanical performance index conversion formula was established. The results show that with the increase of recycled coarse aggregate and rubber particles, the workability and mechanical properties of self-compacting concrete decrease in varying degrees; when the replacement rate of recycled aggregate is 100% and that of rubber is 10%, the cube compressive strength, axial compressive strength and splitting tensile strength of concrete decrease by 31.4%, 31.7% and 26.9% respectively. Compared with the experimental data, the fitting results of the conversion relations of various mechanical properties indexes are better.
The wheel flange wear and rail side wear can significantly be alleviated by wheel flange/rail gauge lubrication; however, the railway tracks are easily polluted and large amounts of grease will be wasted. To solve these problems, laser micro-modeling was prepared on the surface of rail gauge corner, and the feasibility of laser micro-modeling technology applied to wheel flange/rail gauge lubrication was be explored. A TY-FM-20S multi-station rotating fiber laser marking machine was used to fabricate rectangular, circular and rhombus laser micro-textures with different distribution laws on the surface of the rail samples. A large slip ratio was adopted on the MMS-2A friction and wear testing machine to simulate metro vehicles passing through small radius curve sections, and the lubrication simulation tests of wheel flange/rail gauge with different spray oil was carried out. An orthogonal experiment design was introduced to analyze the experiment results, including the visual analysis method and the variance analysis method. The results show that the amount of oil has the greatest effect on the lubrication efficiency, followed by the micro-shape distribution law, and the micro-shape morphology shows the least. Moreover, the rail sample with a rhombus texture, a distribution law of 5.25%（40 shapes） and a 0.2 mL spray oil amount displays the best lubrication efficiency. Thus, it can be concluded that the appropriate laser micro-shape morphology and micro-shape distribution law can significantly improve the lubrication efficiency.
It is a basic requirement for safe construction and normal operation of shield tunneling in soft soil area to study the influence of shield tunneling on surrounding grounds and building settlement. Taking the silty clay layer in the shield section between Longdongcun Station and Longnan Station of Shenzhen Metro Line 16 as the background, a numerical model was established to conduct simulation calculation, and the results were compared with the measured results, so as to study the impact of shield tunneling on the ground surface and building settlement. The results show that after the excavation of the right track, the maximum surface settlement is located at the center line of the right track tunnel, and after the excavation of the left track, the maximum surface settlement is also located at the center line of the right track tunnel; the surface transverse settlement curves caused by single track shield tunneling are all unimodal, while the surface transverse settlement curves caused by double track shield tunneling tend to be bimodal or multi modal; during the right line shield tunneling, the settlement of building monitoring points show an overall downward trend simultaneous with the shield tunneling process. When the left line shield reaches the building monitoring points, the building monitoring points gradually begin to rise. After the left line shield passes, the settlement value of building monitoring points gradually becomes stable.
