Safety Analysis of Lining Structure Influenced by Blasting of Tunnel with Extralarge Section and Small Space

In order to ensure the safety of the Daling tunnel with extralarge section and small space, the three-dimensional model of blasting dynamic simulation had been established and verified. Then, the model was used to analyze the influence of the surrounding rock characteristics and blasting design parameters on the blasting vibration of the first hole, and the analysis of the sensitivity of each factor was carried out. The results showed that blasting of the second hole had a serious impact on the safety of the first hole lining structure. Based on the safety threshold and analysis of sensitivity, the explosive velocity, charge density, and digging length were selected as the key parameters affecting the safety of the tunnel structure. Meanwhile, the corresponding engineering measure was taken based on the results of sensitivity and the actual situation on site, and, after that, the maximum PPV of the right wall of the first hole had been reduced to 9.3 cm/s, which effectively guaranteed the safe construction of the tunnel.

INFLUENCE OF CROWN-WALL ON WAVE OVERTOPPING PROBABILITY AND PROBABILITY DISTRIBUTION OVER A SEAWALL

In the past decades, the crest height of the seawall was determined by the allowable average wave overtopping rate q. Franco (1994) concluded that individual wave overtopping，particularly the maximum individual volume, provided a better design method than q, considering the stability of the seawall and the safety of vehicles and people along the coastal area protected by the coastal defense structures. Shanghai, located on the west bank of the Pacific Ocean, is quite sensitive to the risk of storm surges and violent wave overtopping. The crown-wall serves as an engineering measure to reduce the wave overtopping effectively.

STUDY ON MECHANISM OF BACK-SILTATION IN THE DEEP-DRAFT WATERWAY OF THE YANGTZE ESTUARY, AND EVALUATION OF ENGINEERING MEASURES

Since the 92.2km-long , 350m-wide and -12.5m-deep draft channel was successfully achieved in the South Channel and the North Passage in the year 2010 , high siltation was found to temporally take place in the wet seasons , and spatially concentrate in the middle reach of the North Passage, where is consistent with the location of the traditional turbidity maximum zone (TMZ) of the Yangtze Estuary. The data from 2011 to 2015 show that the average annual siltation in the draft channel reached 80 Million m3 per year. With systematic analysis of the sediment source and comprehensive investigation on the mechanism of the flow and sediment transportation and siltation in the North Passage, this paper reveals a major cause of the back-siltation in the middle reach and subsequently discusses several engineering measures proposed to reduce the siltation . The final-selected engineering measure has been implemented quite recently , and the preliminary study shows that desired effect has been produced by the engineering measure.

Inter-annual change of the drought limit water level of a reservoir based on system dynamics

Drought is one of the major natural disasters affecting the development of economies and society. Drought early warning is the primary step and most important non-engineering measure for drought relief. This paper took Yuqiao Reservoir in Tianjin as a case study and analysed inter-annual changes of the drought limit water level. First, the causality between variables in the water supply–demand system was analysed, and a structural diagram of water sources allocation was drawn. Coupled with the parameters and a structural diagram, a system dynamics (SD) model of the water supply volume was established. Secondly, simulation results were tested to ensure that the model was valid. The water supply volume from 2003 to 2020 was simulated by using the model. Finally, based on the inflow process and the water supply volume, the drought limit water level was calculated. The results showed the water supply volume of Yuqiao Reservoir has changed remarkably. The drought limit water levels in 2003–2012 and in 2016–2020 were 16.70 m and 16.30 m, respectively: a difference of 0.40 m. The regulation curve of guarantee for water supply during 2016–2020 is significantly lower than that of 2003–2012. This research is of great significance for drought resistance, disaster mitigation and reservoir management.

PUBLIC BUS LEVEL OF SERVICE PERFORMANCE IN PENINSULAR MALAYSIA: CORRELATION ANALYSES ON LEVEL OF SERVICE (LOS) AND PASSENGERS’ SATISFACTION LEVEL

This study explore the stage bus performance of 48 routes within selected urban and regional settlements in Peninsula Malaysia, using a quantitative traffic engineering measure known as Level of Service standards or LOS and validated through the evaluation of passengers’ satisfaction level. The findings on the level of service (LOS) highlight the poor performance of the urban and rural bus service with the tolerable threshold below D. There are clear disparities on LOS and passenger satisfaction level between the urban and rural bus operation systems in terms of frequency, operation hour, bus speed, and passengers’ load threshold.

PUBLIC BUS LEVEL OF SERVICE PERFORMANCE IN PENINSULAR MALAYSIA: CORRELATION ANALYSES ON LEVEL OF SERVICE (LOS) AND PASSENGERS SATISFACTION LEVEL

This study explore the stage bus performance of 48 routes within selected urban and regional settlements in Peninsula Malaysia, using a quantitative traffic engineering measure known as Level of Service standards or LOS and validated through the evaluation of passengers’ satisfaction level. The findings on the level of service (LOS) highlight the poor performance of the urban and rural bus service with the tolerable threshold below D. There are clear disparities on LOS and passenger satisfaction level between the urban and rural bus operation systems in terms of frequency, operation hour, bus speed, and passengers’ load threshold.

ASSESSING THE URBAN AND RURAL STAGE BUS SERVICES DISPARITIES IN PENINSULA MALAYSIA

Disparities between services and goods provision have been the concerns of various regional development proponents. Among the gaps that needed to be addressed by regional policies and initiatives were accessibility and mobility levels between urbanites and the rural population. This study reports on the differences of the urban versus rural bus services. For this purpose, this study extends the exploration of approximately 48 routes within selected urban and regional settlements in Peninsula Malaysia, using a quantitative traffic engineering measure known as Level of Service standards or LOS. Three performance measures, namely fixed-route hour of service, fixed-route service frequency and passenger-load threshold were evaluated in determining the existence and extent of such disparities. The passengers’ satisfaction and preference survey were conducted to complement some qualitative explanations left void by the LOS evaluation. Methods of on-board face to face intercept survey and adoption of Geographical Information System (GIS) /Global Positioning System (GPS) were deployed in the collection of primary data. More than 1600 survey forms were distributed, but after collection and data cleaning, only a total of 1130 were analysed. Findings of the study supported and confirmed the existence of such spatial imbalances of services provision. They also further accentuated that many developing nations’ rural settlements were indeed stigmatised by a lower level of stage bus services (average at LOS D) compared to those enjoyed by the urbanites (average services at LOS C).

ASSESSING THE URBAN AND RURAL STAGE BUS SERVICES DISPARITIES IN PENINSULA MALAYSIA

Disparities between services and goods provision have been the concerns of various regional development proponents. Among the gaps that needed to be addressed by regional policies and initiatives were accessibility and mobility levels between urbanites and the rural population. This study reports on the differences of the urban versus rural bus services. For this purpose, this study extends the exploration of approximately 48 routes within selected urban and regional settlements in Peninsula Malaysia, using a quantitative traffic engineering measure known as Level of Service standards or LOS. Three performance measures, namely fixed-route hour of service, fixed-route service frequency and passenger-load threshold were evaluated in determining the existence and extent of such disparities. The passengers’ satisfaction and preference survey were conducted to complement some qualitative explanations left void by the LOS evaluation. Methods of on-board face to face intercept survey and adoption of Geographical Information System (GIS) /Global Positioning System (GPS) were deployed in the collection of primary data. More than 1600 survey forms were distributed, but after collection and data cleaning, only a total of 1130 were analysed. Findings of the study supported and confirmed the existence of such spatial imbalances of services provision. They also further accentuated that many developing nations’ rural settlements were indeed stigmatised by a lower level of stage bus services (average at LOS D) compared to those enjoyed by the urbanites (average services at LOS C).Â