Lessons learned from field measurements in tunnelling

Sakurai, Shunsuke

doi:10.1016/s0886-7798(98)00004-2

Cited by 115 publications

(34 citation statements)

References 2 publications

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“…According to a previous study [6], the modeling of shotcrete with steel ribs in tunnels is similar to the abovementioned modeling case with rock bolts. It is emphasized that shotcrete should not be modeled separately from the ground but should be modeled simultaneously with the ground considering the interaction mechanism between the shotcrete and the ground.…”

Section: Shotcrete Lining With Steel Ribsmentioning

confidence: 93%

Modeling strategy for jointed rock masses reinforced by rock bolts in tunneling practice

Sakurai¹

2010

Acta Geotech.

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This paper deals with the modeling of jointed rock masses reinforced by rock bolts. It is well known that rock bolts are extremely effective in reinforcing jointed rocks. However, if a continuum approach is adopted for modeling jointed rock masses, it is often misleading to evaluate the effectiveness of the rock bolts by numerical analyses such as the finite element method. This may be due to the fact that since no more joints exist in the continuum, the effectiveness of the rock bolts in constraining the relative displacements along the joints cannot be evaluated properly. In order to investigate the reinforcement effect of rock bolts, physical model tests were performed in the laboratory. The test results revealed that jointed rock masses should be modeled as an equivalent continuum after the installation of rock bolts and that the mechanical parameters of the equivalent continuum should be evaluated by considering the reinforcement effect of the rock bolts. Therefore, the values of the mechanical parameters differ from place to place in accordance with the relation between joint orientation and rock bolt direction, even though joint systems are homogeneous. In conclusion, in the continuum approach for modeling jointed rock masses, it should be emphasized that rock bolts and jointed rock masses should not be modeled separately but should be modeled simultaneously by considering the reinforcement effect of the rock bolts in constraining joint movement. The modeling of shotcrete reinforced by steel ribs is also discussed in comparison to the modeling by rock bolts.

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Section: Shotcrete Lining With Steel Ribsmentioning

confidence: 93%

Modeling strategy for jointed rock masses reinforced by rock bolts in tunneling practice

Sakurai¹

2010

Acta Geotech.

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“…In open pit mines different forms of monitoring systems have been used to predict slope stability (Sakurai 1997). Previously monitoring points were fixed in the field and monitored periodically, whereas with the recent technology more improved systems such as slope monitoring radar have been used.…”

Section: Monitoring Of Mining Operationsmentioning

confidence: 99%

“…Numerical model calibration is a way of reliably estimation of strength properties of rock mass and reduction of uncertainties (Sakurai 1997). The calibration studies include the comparison of modelling results with the field measurements.…”

Section: Monitoring Of Mining Operationsmentioning

confidence: 99%

Computational monitoring in real time: review of methods and applications

Dyskin

Başarır

Doherty

et al. 2018

Geomech. Geophys. Geo-energ. Geo-resour.

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Continuous monitoring of mechanical parameters determining the state of natural and manmade systems is essential in a wide range of engineering disciplines from mechanical to civil and geotechnical engineering. To be effective, the monitoring response time needs to be commensurate with the characteristic time of variation of the processes being monitored e.g. from seconds as for example in some machinery, to weeks and months for mining excavations and years in the case of structures. The methods of measurement can therefore differ significantly for different applications. In spite of this, the methods of information processing-the computational monitoring-have considerable commonality. This review focuses on the methods of computational monitoring in solid and structural mechanics problems in different engineering applications. The traditional methods of monitoring are reviewed along with the corresponding computational and measurement methods. The basic principles of the computational monitoring in real time are established.

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“…The critical strain (authority) is one of the ways by which can be considered to measure the displacement of the tunnels like subsidence crown and convergence which is always smaller than the failure strain. Sakura relating the laboratory Results and field data were obtained a relationship between the critical strain and compressive strength and Young's modulus and three levels warning of the danger presented as follows [13] …”

Section: Static Analysismentioning

confidence: 99%

“…Strain curves and modeled displacement in this depth and finally calculated displacement and safety ration is presented in (Table 8) which is the result of numerical modeling. After calculating the critical strain with use of Equation (8), we can calculate the safety ratio in any depth which is based on the following equation [14]:…”

Section: Static Analysismentioning

confidence: 99%

Analysis of Geomechanical Properties in Terms of Parametric Discontinuities on Stability of Tunnels Distinct Element Method (Case Study: Water Tunnel of Golab)

Dehnoo¹,

Mirzeynali

Farrokhnia

2015

OJG

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The discontinuities of the rock mass pose a high impact on its response to the static load and make complexity in modeling in such area. Principal objective of this study is to analyze the stability and sensitivity of Golab transfer tunnel access (transfer water from Zayanderud River to Kashan). This tunnel with a length of 5.1 kilometers and inclination of 13.5 percent is located 120 kilometers from Isfahan city. Geologically, this zone is in the range of sediment structure of Sanandaj-Sirjan. The host rock mass consists of Limestone Mesozoic (Cretaceous). The general characteristics of the joints in the rock represent high distance, low persistence, low opening (2 -3 mm), average roughness and low weathering. Given purpose of the project and the distinct element method is the most useful for modeling rock mass for static analysis. This paper examines the effect of parametric factors on the stability of tunnels via UDEC software, discrete element and empirical method. After modeling, instability of Golab tunnel by increasing the depth is identified and confirmed. RMR, Q and GSI as experimental procedure were employed to classify the rock mass, based on RMR classification. The route rock mass has been taken in I and II categories and based on the Q classification, the path rock masses are recognized acceptable.

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Lessons learned from field measurements in tunnelling

Cited by 115 publications

References 2 publications

Modeling strategy for jointed rock masses reinforced by rock bolts in tunneling practice

Modeling strategy for jointed rock masses reinforced by rock bolts in tunneling practice

Computational monitoring in real time: review of methods and applications

Analysis of Geomechanical Properties in Terms of Parametric Discontinuities on Stability of Tunnels Distinct Element Method (Case Study: Water Tunnel of Golab)

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