Transport carriers’ cooperation on the last-mile delivery in urban areas

Transportation - A sharing logistics platform for less-than-truckloads could increase efficiency in city pickup and last-mile deliveries under time window constraints by pairing (matching) truck...     

Organizational and Ownership Transformation in Poland’s Urban Transport Companies

Abstract

This paper seeks to reconstruct the organizational and ownership transformation involving Poland’s urban transport that companies passed through after 1990. Data collected from various sources (above all the Internet, including the Bulletins of Public Information) were used to establish the degree of advancement of the transformation processes. Despite the passage of nearly two decades since the new economic reforms were launched, the privatization processes involving enterprises of municipal origin are not well‐advanced. There is not a single private company among the organizers of urban transport. Instead, an absolute domination of budgetary‐sphere entities may be noted. Furthermore, there are seven transport municipal unions. Among the operators (carriers) public ownership remains dominant in the form of single‐person local authority companies, local government companies, municipal union ownerships, municipal companies as well as budgetary units. Privatization processes have encompassed fewer than 10% of all operators in the form of companies with foreign participation, workers’ companies and companies with Polish non‐public sector participation. Moreover, in 20 localities urban transport is supplied by multi‐trade municipal services enterprises (as of end‐2008). Thus, transformation processes, though started earlier than in the case of Poland’s State Road Transport coach companies, are much less advanced.     

Study on Reinforcing Technology System for the Overlapped Running Shield Tunnels underneath the Track Group of High Speed Railways北大核心CSCD

The large settlements of tracks will emerge due to multiple disturbances in the construction of over- lapped shield tunnels, which affects the running safety of trains. Based on the overlapped Sungang station-Honghu station shield running tunnels of Shenzhen Metro line 7 passing underneath 26 tracks of high speed railways, a rein- forcement technology system consisting of”track support + subgrade reinforcement + interlayer soil consolidation + internal support of the lower tunnel”was developed. The settlements of tracks were mainly monitored automatically with manual monitoring as an auxiliary one. The results show that the maximum settlement of main track caused by constructing overlapped shield tunnels is -5.9 mm which is less than the control value of 10 mm, ensuring the opera- tion safety and verifying the reliability and practicability of the reinforcement technology system. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved.     

Model Test Study on’Lost’Deformation and Corresponding Control Measures in Soft Rock Tunnels with Extremely High Ground Stress北大核心CSCD

In order to study the laws of core rock deformation and’lost’rock deformation in soft rock tunnels with high ground stress, the deformations of core rocks in front of the working face and surrounding rocks are monitored by model test method, and the tunnel excavation process is simulated in detail under different high ground stress levels and working conditions with/without lining. The results show that: (1) the ground stress plays a key role in determining the installation time of soft rock tunnel support; (2) the advance deformation within 0.5D in front of the face accounts for about 2/3 of the total advance deformation; (3) the’lost’deformation behind the tunnel face has a great impact on the monitoring and measurement. With a certain high ground stress, there is a power function relationship between the’lost’deformation and the distance from the tunnel face. With the high ground stress greater than 20 MPa, it has little impact on the’lost’deformation; (4) in order to effectively control the advance deformation in soft rock tunnels with high ground stress, it is necessary to reinforce the core rock mass within 0.5D in front of the tunnel face. For the core rock mass within 0.5D~1D in front of the tunnel face, the reinforcement depends on the actual situation. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved.