new rate for excavation of hard rocks of the year É2

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Three-dimensional stress variation characteristics in deep hard rock
2024.2.1 In deep hard rock excavation, stress plays a pivotal role in inducing stress-controlled failure. While the impact of excavation-induced stress disturbance on rock failure
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Influence of excavation stress paths on failure feature of deep hard rocks
2023.9.2 Deep hard rock excavation is prone to brittle disasters such as rockburst and spalling, which directly affect engineering safety. However, the fundamental cause of deep
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Hard rock drilling characteristics under axial-torsional
2024.9.1 Results indicate that an increase of 129.42% in penetration depth and 91.18% in ROP is obtained at the A-T impact frequency ratio of 1:1 compared to conventional rotary
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Tunnelling and Underground Space Technology
2019.8.31 The typical utilization rates range from 5% for very difficult and complex geologies with poor site management to around 55% in perfect working conditions for an open
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A New Model for Performance Prediction of
A new theoretical/empirical model has been developed for performance prediction of hard rock TBMs. The model uses information on the rock properties and cutting geometry to calculate TBM rate of penetration. The model can also be used
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Multi-step real-time prediction of hard-rock TBM penetration rate ...
2024.6.21 To address these challenges, we propose TCN-SENet++, a novel hybrid multistep real-time penetration rate prediction model that combines a temporal convolutional
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Prediction of TBM cutterhead speed and penetration rate for
2022.1.29 From the R2 perspective, the prediction of cutterhead speed improved by 0.02, and the prediction of penetration rate improved by 0.07 in the first 60 s of rising phase data.
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Benchmark drill and blast and mechanical
Weekly advance rate as a function of tunnel cross section and equipment combination is presented, by applying the model for 5 m drillhole length, 48 mm drillhole diameter, parallel hole cut, medium blastability and drillability, medium
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Time-dependent failure characteristics of excavated rock
2022.12.2 Through true triaxial creep test, the time-dependent fracture process of deep hard rock is simulated, so as to reveal the time-dependent failure mechanism of hard rock
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Rockburst response in hard rock owing to excavation unloading of
2021.7.30 This study aims to investigate the rockburst characteristics of hard rock during the successive excavation unloading of twin circular tunnels subjected to high active stresses. The entire evolution process of the rockburst phenomena around the tunnels is reproduced. The numerical results indicate that the unloading rates, burial depths, and presence of structural
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Design Aspects Governing Disc Cutters and Cutterheads of Hard Rock
2024.1.31 Tunnel boring machine (TBM) has been in focus for the last few decades and is currently the most preferred excavation method for metro, hydro and irrigation tunnels. Tunnelling in hard and abrasive rock conditions, in particular, is adversely affected by a very low advance rate coupled with increased TBM disc cutter failures and cutterhead jamming, seeking an in
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Prediction of TBM cutterhead speed and penetration rate for ...
2022.1.30 Cutterhead speed and penetration rate are two key operating parameters that hard-rock tunnel boring machine (TBM) operators control to minimize the risks associated with high capital costs and scheduling for tunnel excavation. This paper introduces a ...
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Dynamic Strength and Indentation Hardness of a Hard
2023.12.15 1.3 Excavation Rate and Mechanical Properties of Rocks The strength and hardness of rocks can inuence the excava - tion rate of tunnelling. Rocks with higher strength and hard-ness can result in a ...
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Influence of excavation stress paths on failure feature of deep hard rocks
2023.9.2 The fracture of the surrounding rock in deep hard rock engineering is influenced by the stress path during excavation. Taking the stress path as the only variable, a true triaxial experimental system was used to study the loading–unloading stress path during excavation and the loading stress path with constant stress state after excavation, and combined with acoustic
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Excavation-induced deep hard rock fracturing: Methodology
2022.2.1 A new rock mechanics research system with a focus on the excavation-induced deep hard rock fracturing process has been established, and significant progress has been made. Numerous testing techniques for determining the mechanical properties and fracturing process of hard rocks under true triaxial excavation stress paths have been developed.
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Excavation Stress Path Induced Fracturing Mechanism of Hard Rock
2022.12.7 Excavation of deep hard rock tunnels disturbs the initial stress imbalance, which can lead to rockburst, spalling and/or collapse. The disasters are related not only to the strength of the rock mass, but also to the excavation stress path. By analysing and summarizing a large number of engineering cases, the surrounding rock of a deep tunnel is divided into high-,
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Influence of Excavation Inner Diameter on the Unloading
2024.3.12 The developing trend in tunnel engineering is toward the expansion of the tunnel’s inner diameter, which is bound to affect the deformation of the tunnel surrounding rock. To address this problem, transient and slow unloading tests of small thick-walled cylindrical surrounding rock specimens made of natural sandstone with different inner diameters are
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COMPARISON BETWEEN CSM AND NTH HARD ROCK
2024.3.7 The important issues related to the performance and cost estimation of hard rock Tunnel Boring Machines (TBM) are presented and discussed in this paper. General
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Wear of Cutting Tools in Hard Rock Excavation Process: A
2022.12.15 Increasing demand for the use of different mechanized excavation systems in civil and mining projects has elevated the importance of understanding the wear process of rock-cutting tools. This requires proper measurement and analysis of rock abrasiveness and cuttability characteristics. Predicting the wear life of cutting tools, evaluating the required number of tools
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A new excavation technology of blasting
2021.11.17 1. Introduction. The technical feasibility of drilling and blasting or TBM excavation method is one of the key factors for underground engineering (Bruland Citation 1998 a, Citation 1998 b; Barton, Citation 2000; Bieniawski et
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Advance rate simulation for hard rock TBMs - Springer
2014.3.22 The existing methods for estimating the advance rate of hard rock Tunnel Boring Machine (TBM) often involves estimation of the machine utilization in a direct or an indirect manner. These methods are based on empirical systems and are limited in their capacity for incorporating new machine capabilities or including many of the geological features along the
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A New System to Evaluate Comprehensive
2019.12.5 The accurate performance evaluation of a cutterhead is essential to improving cutterhead structure design and predicting project cost. Through extensive research, this paper evaluates the performance of a tunnel
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Introducing Tree-Based-Regression Models for Prediction of Hard Rock ...
2022.5.25 Prediction of machine performance is a fundamental step for planning, cost estimation/control and selection of the machine type when using a tunnel boring machine (TBM). Penetration rate (PR) and machine utilization (U) are the two principal measures of TBM performance for evaluating the feasibility of using a machine in a given ground condition.
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Evaluating the Efficiency of a New Cutterhead Design to
2021.6.2 The application of appropriate excavation equipment in difficult grounds is of crucial importance and consequently improves the performance of hard rock Tunnel Boring Machines (TBMs). The cutterhead is one of the main components of TBMs which is directly involved in the excavation process, and its design can highly affect the cutting efficiency, the
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Rate Analysis of Excavation in Earthwork: November 2024
6 天之前 Rate analysis of excavation in earthwork use of IS Code 1200 part 1, Part 27, IS 4988, IS 12138 (Part IV) and CPWD for calculation is this measurement of the quantity of excavation to be carried out, the cost of labour, machinery, and other equipment like hard soil for breaker, etc.. Rate analysis of excavation depends on the depth of excavation, depending on soil type, also
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Influence of excavation stress paths on failure feature of
2024.3.14 Deep hard rock excavation is prone to brittle disasters such as rockburst and spalling, which directly affect engineering safety. However, the fundamental cause of deep hard rock failure is the adjustment of the stress state caused by excavation, which means that the rock will experience a loading-unloading stress path [3, 4, 11, 30, 38].
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Prediction of TBM cutterhead speed and penetration rate for
2022.2.1 Cutterhead speed and penetration rate are two key operating parameters that hard-rock tunnel boring machine (TBM) operators control to minimize the risks associated with high capital costs and ...
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A flexible system for selection of rock mass excavation method
2020.6.19 The excavation of rock masses has a crucial importance for the safety and cost of construction of engineering projects. In this study, a flexible excavation assessment (EXCASS) system was developed with two components, the geological strength index (GSI) and the point load strength index (Is50). In order to develop the system, artificial neural network (ANN)
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Excavation unloading‐induced fracturing of hard rock
2019.9.27 Slabbing failure and strain rock burst are the main failure patterns during the excavation and construction phases of deep tunnels in hard and brittle rock, which cause unexpected equipment damage and casualties. This study presents a numerical simulation with an unloading central hole within a hard rock specimen in the laboratory scale.
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