Key technologies of drilling process with raise boring method
To this end, the large raise boring machine, drilling process, rock breaking and shaft wall stability during raise boring should be studied (Liu, 2001, Zhang et al., ... Deviation rate of pilot hole is a ratio of raise length to the maximum deviation. Deviation of pilot hole is generally caused by anisotropy of strata, machining accuracy of ...
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An Optimization Methodology of Cutter-Spacing for …
Published: 15 February 2022. An Optimization Methodology of Cutter-Spacing for Efficient Mechanical Breaking of Jointed Rock Mass. Kanglei Song, Haiqing Yang, Junning Xie & …
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Experimental and simulation study on rock-breaking …
The test involves the preparation of large rock blocks (Fig. 1 a) and concrete-pouring to fill the gaps between the rock blocks (Fig. 1 b), a suitable rotary cutter rock-breaking test bench (Fig. 1 c), the design of the test steps, the collection and particle size analysis of the crushed rock after rock breaking (Fig. 1 d), etc. The cost, time ...
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Theoretical and numerical studies of rock breaking
This study aims at determining the stress distribution law in the rock mass by establishing a two-dimensional plane mechanical model of rock breaking with double …
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Numerical simulation study on rock-breaking process and mechanism …
Shearing with polycrystalline diamond compact (PDC) bits is currently the most effective rock-breaking process (Deen et al., 2011, Gao et al., 2020) and is widely used in oil and gas drilling (Bellin et al., 2010, Cheng et al., 2019).However, as depth of reservoirs explored increases, the rock formations encountered during the drilling …
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Rock Adaptability of TBM Variable Cross-section Cutter Ring …
The tool system is integral to the tunnel boring machine (TBM). Its performance is directly related to TBM tunneling efficiency and reliability (Herrenknecht et al. 2008).The ring of the disc cutter is the part that directly contacts the rock, so the cutter ring is critical to breaking the rock (Liu et al. 2016a, b).After years of development, the disc …
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Influence of Height–Diameter Ratio on Rock Compressive …
In underground projects such as mining and tunneling, the presence of coal rock columns plays a certain supporting role, and the instability of coal rock columns is often related to their size and shape of presence. Therefore, in order to investigate the compressive damage characteristics and damage evolution law of rocks of different sizes, …
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Distribution characteristics of rock chips under relieved and
Mineral cutting and breaking is the first step in deep-sea mining. To investigate the effects of hydrostatic pressure on the rock cutting process, this study analyzed cutting force, specific energy (SE), and debris distribution parameters (coarseness index CI, debris size parameter d e, debris size uniformity n, fractal dimension D) under …
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The rock breaking and ROP increase mechanisms for single …
Torsional impact drilling is a new technology which has the advantages of high rock-breaking efficiency and a high rate of penetration (ROP). So far, there is no in-depth understanding of the rock-breaking mechanism for the ROP increase from torsional impact tools. Therefore, it has practical engineering significance to study the rock …
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The rock breaking mechanism analysis of rotary percussive …
The MSE is defined as the ratio of the total work done by PDC cutter to rock breaking volume, it is one of the important index to evaluate the rock breaking efficiency which first proposed by Teale, MSE = W/V = FL/LS = F/S. Where L is the cutting length, S is the contact area between cutter and rock, and F is the average cutting force.
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Research on the mechanism and performance of free …
The effect of breaking depth on rock breakage performance was experimentally and numerically investigated under the conditions of tip width, inclined …
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A Study of Optimal Rock-Cutting Conditions for Hard Rock …
The efficiency of TBM performance affected by the specific s/p (s: spacing and p: penetration) ratio of the disc cutter is a research issue in demand. This article presents a multi-indentation simulation using discrete element method (DEM) analysis to study the optimal rock-cutting phenomena in terms of the interaction of the s/p ratio with …
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Identifying Effective Rock-Breaking Ratio Based on Rock …
P r is used to evaluate the rock-breaking efficiency of TBM based on the proportion of surface area of rock chips with particle size larger than 5 mm; (2) P r has a good linear correlation with ...
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(PDF) Comparison study on rock breaking …
PDF | On Jan 12, 2023, Laikuang Lin and others published Comparison study on rock breaking characteristics of disc cutters under coupled static–dynamic loads and static loads | Find, read and ...
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Rock Mechanics and Rock Engineering | Online first articles …
Longke Wu. Original Paper. Published: 01 November 2023. 1. 2. 3. Online first articles listing for Rock Mechanics and Rock Engineering.
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The mechanism and performance of rock breakage …
The rock breaking specific energy consumption decreases with as the cutting thickness increases, and there is a good linear relationship (R 2 = 0.92). When the …
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Numerical simulation and experimental studies of …
In this study, to compare the rock-breaking performance in different modes, the experimental and numerical simulation researches on rock breaking by the disc …
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Rock Chip Properties of TBM Penetration in Jointed Rock
The combined influence of joint spacing and angle on the rock breaking process and rock chip properties were analysed. Further, a rock chip extraction algorithm was proposed to quantify the shape and size distribution. ... The mid-axis to long-axis ratio of the rock chip, ... Hard rock tunnel boring machine penetration test as an indicator of ...
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Evaluation of the energy efficiency of rotary
As a result, the modified expression was obtained for application of the volumetric rock destruction energy criterion (VDEC) in the engineering of rock-breaking tools for down-the-hole rotary percussive drills: (19) k = E 0 α V ρ υ p 2 = (1 − 4) × 10 − 9 where α is the coefficient of impulse rock-breaking effect exerted by percussive ...
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Investigating the cutting force of disc cutter in multi-cutter …
Most early studies in this domain were based on theoretical analysis. Evans 1 proposed a formula for calculating the normal force by analysing the contact between the disc cutter and rock. They suggested that the normal force required for rock-breaking with a disc cutter is proportional to the projected area of the disc cutter pressed into the rock …
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(PDF) A REVIEW OF EXPLOSIVE-FREE ROCK BREAKAGE (EFRB …
Mechanical rock breakage equipment such as tunnel boring and raise boring machines, road headers, continuous miners, and longwall drum shearers have been developed to break rocks with the aim of ...
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(PDF) An updated formula and method to predict the performance …
Aksoy (2009) and Aksoy et al. (2013) investigated the effects of the machine power, the geological strength index, block punch index and the weak rock breakability index on breaking performance of ...
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Rock Recognition Using Stereo Vision for Large Rock Breaking …
1 Introduction. This paper concerns rock recognition by means of stereo vision that will be for rock breaking operation of a hydraulic breaker (an excavator with a hydraulic hammer) in an open-pit quarry. The motivation of this research arises from an of the operation. At the work front in a quarry, since some of the rocks generated by rock ...
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Water | Free Full-Text | Simulation of the Compaction …
The rock mass in the caving zone of a goaf is relatively broken and considered a porous medium. Additionally, it has the characteristics of irregular size and shape and sharp edges, and it is easy to break. In the process of caving zone compaction, the shape characteristic of a broken rock mass is one of the most important factors …
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Experimental and simulation study on rock-breaking …
There are many studies on rock-breaking efficiency of TBM's disc cutters on homogeneous rocks; however, there are few studies on the cutter's rock-breaking efficiency on composite rocks.Specifically, research on the breaking efficiency of cutters on composite rocks with substantial differences in strength and composite ratios has not yet been …
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Experimental and simulation study on rock-breaking …
Given the fact many studies on rock-breaking efficiency of TBM's disc cutters are on homogeneous rocks, but rarely on composite rocks with significant differences in …
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Research on the mechanism and performance of free-surface rock …
The optimal rock breaking performance was obtained when the tip width was approximately 1 mm. Compared with the traditional rock breaking method, the preslotting method can significantly reduce the cutter load. ... Tunnel boring machines ... Poisson's ratio: 0.29: Normal-to-shear stiffness ratio: 2.5: UCS /MPa: 86: Tensile strength (pb_ten) …
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Q&A about concrete and rock breaking chemicals
It matters not if it is a concrete demolition, rock cutting or other type of rock breaking. The optimal mixing ratio is 1.0 litre of water to 5 kg of BETONAMIT® (34 oz / 11 lbs). The water content can be increased up to 1.2 litre / 5 kg (40 oz / 11 lbs) in order to achieve improved fluidity, especially for very deep boreholes, or to facilitate ...
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Performance prediction of TBM disc cutting on granitic rock …
Rock cutting volume (V) can indicate both the rock muck production rate (i.e. machine excavation output) and the rock breakage surface morphology (i.e. rock under-breakage or over-breakage) (Abu ...
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Stress and Wear Analysis of the Disc Cutter of Rock …
The effects on the rock breaking from limiting stress at the process of cutting rocks have been studied by Ma [6]. Vibration characteristics and wear of the disc cutters were studied by Tanimoto [7]. The arrangement of disc cutters on the cutter head has been optimized by Zhaohuang Zhang [8]. The main parameter of the machine has been studied based
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