Tunnel monitoring and measurement is a very important part of the tunnel construction safety andit is one of the important contents of tunnels on Railway Passenger Dedicated Lines segment acceptance, Its purpose is through the tunnel clearance convergence and settlement observation,to analysis data, optimize tunnel construction and design, and determine a reasonable safety step and support time, protect tunnel construction and operational safety, Although the domestic and foreign on tunnel monitoring measurement work are very seriously, but at present the requirements of monitoring level and information construction are far away. This article based on 3D laser scanning technology, proposed tunnel 3D laser scanning measurement and data visualization technology, through the engineering application and practice, the results show that the technique can be real-time, accurate and comprehensive to get the deformation data of tunnel space,and can analysis and counter-analysis the deformation of tunnel construction, it has greatapplication value of engineering for early warning forecast the risk and guidingtunnel construction.
This paper presents the results of an experimental investigation to determine the flexural fatigue strength and fatigue life of concrete beams reinforced with monofilament polyacrylonitrile fibers (PAN fiber for short). The performance of fresh concrete and the elastic and mechanical properties of hardened concrete are compared by samples with and without fibers. The toughness calculated according to both ASTM and JCI methods increased with the addition of fibers. The toughness indexes I5 was 3.8-4.2 times,I10 was 5.8—6.8 times that of the plain concrete. The equivalent strength was 0.63-0.87 MPa for PAN fiber reinforced concrete. When compared to plain concrete, the endurance limit of concrete beams only reinforced with PAN fiber is increased by 12 percent.
The methods of controlling Highway semi-rigid base asphalt pavement cracks and other diseases are always hot fields of road engineering and academic circles. The existing methods are on some degree efficient on delaying the formation and extension of cracks, but the effect is limited with different methods and various mechanisms of preventing cracks. Base on force analysis of pavement, this article presents a new technology of crack controlling which uses intelligent composite materials interlayer. By adding a stress absorbing layer between the asphalt surface layers or the semi-rigid base layers with low modulus, good toughness, self-adaptability and self-control ability, the intelligent composite materials interlayer has a good effect on controlling cracks which has been proved by the theoretical calculations and experimental analysis. As a result, the intelligent composite materials interlayer could efficiently prevent and delay the formation and extension of cracks, the safety and comfort of highway could be improved significantly while the cost of construction and maintenance decreasing. And the service level and social image of the road could also be improved effectively. This research has important academic and application value.
Based on the practice of Huolang-yu tunnel of Mixing road reconstruction, this paper studies the monitoring of ground surface vibration and the technology of controlled blasting. The results show: (1) the ground surface vibration declines from constructed position to non-excavated areas along tunnel excavation direction. (2) The vibration control of wedge cutting holes blasting is the key to reduce or eliminate shallow tunnel vibrating calamity. And the replacement of the multi-stage small wedge cutting holes to the big wedge cutting holes ameliorates blasting vibration and rock fragmentation. (3) The overall monitoring of shallow tunnel blasting vibration and the effects, and optimum of the blasting design not only reduce blasting vibration but also ensure large circulation footage.
Tunnel monitoring and measurement is a very important part of the tunnel construction's safety,monitoring technology and information management technology is directly related to the tunnel construction's safety and quality, Although domestic and foreign scholars have done a lot of research on tunnel monitoring measurement technology and information management technology,because of the characteristics of invisibility, uncertainty and variability in tunneling, the level of the monitoring technology and information management are far from construction's requirements.This paper based on ACCESS and GTS, researching and developing automatic warning system of tunnel monitoring,and realizing the information management and early warning forecast of tunnel monitoring measurement data. Engineering practice shows that the system can processing and analyzingthe data fast, convenient and real-time , realize automatic early warning forecast, and provide reliable basis for information construction management of tunneling
At present, both at home and abroad of tunnel surrounding rock classification methods and standards are all aimed at tunnel survey and design phase. It is the cause of that surrounding rock classification are very different between design phase and tunnel construction because of the limits of investigation techniques and geological data. It is the key to the real-time construction design problem that Sentenced to a stable state of surrounding rock based on the monitoring data. This paper determines the influence factors of tunnel convergence value clearance and obtained the tunnel convergence value clearance of principal component factor and power based on the statistical analysis of a lot of tunnel monitoring measurement data. It is put forward correction formula of dynamic classification of surrounding rock according to the theory of probability and statistics. The results show that based on the real-time monitoring of tunnel surrounding rock classification method is quite coincident with the actual situation of tunnel excavation in engineering applications.
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