The effect on residential life for the tunnel construction
With the appearance of tunnels in the city or downtown, residential life and building is influenced inevitably by drilling and blasting construction at the entrance of tunnel. In order to reduce the effect, the monitoring of effect on resident, such as dust and noise was conducted during the construction of the entrance of tunnel. The monitoring result shows: (1) Dust content is 20 mg/m3 at the entrance of tunnel for blasting. It is 60 mg/m3 during the construction of wet pneumatically placed concrete. It is higher than the standard of health, 5.3 mg/m3. (2) Noise is 85 decibels when ventilation and noise is 200 decibels during the construction of drilling that is more than the standard, 60 decibels. It provides the reference for similar engineering.(3)The surface settlement induced by drilling and blasting in tunnels affects residential life.
UDEC modeling of a field explosion test
A field explosion test is conducted to investigate the blast wave characteristics and propagation in jointed rock mass. A hybrid AUTODYN and UDEC scheme is used to predict the rock mass response due to the explosion. The original prediction is then modified by involving the actual test conditions and dynamic equation of state of the rock material. Correlating the prediction results with the field explosion test results shows that the hybrid AUTODYN and UDEC scheme is capable of modeling explosion problems with high reliability. It is observed that the modified prediction result agrees better with the field test result than the original prediction result, which implies that involving dynamic parameters in the modeling is very important to produce reliable prediction results.
Design of reinforced concrete lining in pressure tunnels, considering thermal effects and jointed rockmass
Abstract Jaeger's theory (Jaeger, Rock Mechanics and Rock Engineering , Cambridge University Press, 1972) of the design of the lining for a pressure tunnel applies to a tunnel located in an isotropic, homogeneous and elastic medium. The theory is derived from the elasticity equations for the plane stress condition. In this paper, Jaeger's theory is extended to a plane strain situation. Also included is a discussion of the effects of a uniform increase (or decrease) in the lining temperature, jointed rockmass, cracking of the tunnel lining, and cracking of the rockmass around the opening. Tables are presented for the modulus of subgrade reaction for various rockmass conditions and for rock sharing pressures for various lining conditions. The reduction factor to include the effect of joints in rockmass is derived by the analysis of a numerical model of the lined tunnel by the finite-infinite-interface element method.