The number of crashes occurring on motorway exit slip roads is approximately double that occurring on entrance slip roads. A crash on an exit slip road usually causes a decrease in its capacity, leading to queues forming on the main carriageway. The aim of this paper is to evaluate the safety factors for exit slip roads on urban motorways in China. Seventy exit slip roads on motorways in Shanghai were selected for statistical and regression analyses. Negative binomial models were established to identify the influencing factors. The regression results indicate that the slope of the exit slip road, the length of deceleration lane, the length from the slip road terminal to stop line, the exit slip road type and the average annual daily traffic are significant factors with respect to the safety performance of exit slip roads. Compared with previous studies, urban motorway exit slip roads in China have complex and specific influencing factors. With the exception of the geometric design of exit slip roads, the slip road–street intersection serves an important role in slip road safety.
The damage caused by blasting vibration on rock mass is an extremely complex process, and has certain impact on the mechanical properties and bearing capacity of the rock, which will affect the overall stability and safe operation of the construction. Therefore, studying on the damage effect of blasting vibration is very necessary. Taking Laxiwa hydropower station project as a background, the paper computed relative velocity response spectrum using monitoring and measuring blasting velocity as an excitation, then analysis was carried out to study the relationship between the depth of rock blasting and the integral value of relative velocity response spectrum as well as the index of cooperation of the integral value and the blast vibration’s duration time. The results show that using three-parameter (velocity, frequency, duration time) was clearly superior to two-parameter (velocity, frequency) on studying the damage fracture of rock blasting, and two-parameter was better than one-parameter (velocity) by analogy.
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