Selecting the shape and bracing for excavations

Stazhevskii, S. B.

doi:10.1007/bf02504141

Cited by 3 publications

(1 citation statement)

References 6 publications

(10 reference statements)

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“…5a). The evolution law is the same for the two of the processes [11]. Figure 6b (from [12], with slight changes) illustrates rock mass deformation in a karst area of the Perm region in Russia after an explosion and collapse on 23-24 June, 1986.…”

Section: Karst and Sinkhole Formationmentioning

confidence: 99%

Origination and development mechanics of the Earth’s morphostructures. Part II: The nature of diatreme, karst and trappean formations, and the chicxulub crater origin

Stazhevsky

2012

J Min Sci

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The article analyzes genesis of representative morphostructures of the Earth, and substantiates that their origin, similarly to the Patomsky crater, is associated with the hydrogen outgassing and pipe formation in the internal part of the Earth, or, to put it otherwise, with the development of different diameter ring shape structures in the hard shell of the planet. Evolution of all the structures can be described with the dilatancy-explosion model, independent of their dimension. The author explains the billions years history of integration of these endogenous structures into great families of different scale, age and depth ring structures. It is shown that this global process is based on the plume-tectonics.A "kimberlite diatreme" origination involves pipe formation and eruption, similarly to the genesis of the Patomsky ring structure (ring structure are hereinafter put as RS) [1], though the mechanism of these processes remains unclear [2]. According to [1], the pipe formation process provides degassing of the subsoil having the solid outer jacket, and the eruption is associated with the presence of explosive gases, such as Н 2 , СН 4 , СО etc., during the outgassing. These notions make up the basis for a dilatancy and explosion model of cratering (or an RS formation) that allowed explaining the Patomsky crater genesis. Figure 1 shows experimental results with sand to simulate pipe formation in the subsoil. The pipe formation phenomenon is a result of deep-level processes, it starts with a focal zone and goes on as subsequent localized shears along conical and cylindrical rupture lines (RL1 and RL2, respectively, in Fig. 1) with a step l governed by a diameter 0 d of the "focus" and the strength of surrounding rocks. Localized deformation surfaces form a cylinder channel in geo-environment, the channel is filled with a granular block-structured medium. The rupture lines act as the maximum softening zones in the substrata and turn into conductor tracks for fluids toward the earth surface.The Patomsky crater originated as a result of collision and mix of juvenile gas and free air at depth 0 0in the said channel, followed with eruption and rock column displacement from the depth 0 h to the surface, and ended with the fall of rocks back into the formed hollow pipe with the height 0 h [1]. The other consequences of the Patomsky RS are (1) a trough-like depression, coaxial with the crater but with larger diameter, with a "root" as the long-living downward-tapered softening zone; (2) concentration of fluids in the softening zone, including waters; (3) increase in the content of these fluid from the said zone periphery to its center; (4) alteration of geophysical fields in radial direction in this zone; (5) appearance of mixed broken crustal rocks, local soil and vegetation at the top near the zone axis.

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Section: Karst and Sinkhole Formationmentioning

confidence: 99%

Origination and development mechanics of the Earth’s morphostructures. Part II: The nature of diatreme, karst and trappean formations, and the chicxulub crater origin

Stazhevsky

2012

J Min Sci

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Deformation and failure of sedimentary rock around permanent and development mine workings

Shtumpf¹

1990

Soviet Mining Science

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Problems involving improvement in the stability of mine workings in Kuzbass mines assume increasing significance in connection with an increase in the depth of exploitation and the introduction of deposits and segments with complex geologic-mining conditions to service.Long-term field observations at mines operated by the Production Unions "Yuzhkuzbassugol', ~ "Leninskugol'," and "Severokuzbassugol'" and laboratory investigations of the strength, elastic and other mechanical properties of enclosing rock have been conducted to determine the effect of the basic components of the structure and the mechanical properties of ore on the character and degree of their failure around permanent and development workings. The displacement and foliation of the rock was investigated using face and depth benchmarks (with a length of up to 6-7 m), and the character and mode of the failure of rock around workings was recorded during their service outside and inside the zone of influence of cleaning operations and during rebracing of workings with the tapping and removal of fractured rock.The investigations that we performed and data derived from practice indicate that the character of failure of the rock around a working depends primarily on its structure and texture -stratification, jointing, cleavage, slip furrows, slip surfaces, and other structural macrodefects, the intensity of the macrodefects, and their arrangement in the mass with respect to the perimeter of the working.When uniform weak and very weak rock of massive texture without pronounced macrodefects in the structure primarily with an ultimate uniaxial compressive strength Oco m < 30-40 MPa is bedded in the vicinity of workings, the failure of rock in the roof of a level working assumes a shape close to that of a perfectly contoured arch (curve 1 in Fig. i). According to data of mine observations, the maximum height bma x of the primary arch of rock failure and collapse is a component part of the length s of the working in the opening b ..... = (0,2--0,4)/.The angle of incline @ of the slip surface and collapse of roof rock to the horizontal axis is 70-85~ in this case, a reduction in rock strength is accompanied by an increase in the angle O to 82-85 ~ .Critical deformations and failure spread into the rock from the sides and floor of the working with increasing mine pressure, and the failure perimeter of the rock around the working assumes a horseshore, elliptical, or circular shape. Under these conditions, the height of the critical deformations and collapses of rock in the roof of the working reaches (1.5-2)s i.e., 1.5-2 times its maximum width in the cut. Fracture and displacement of the weak and very weak homogeneous rock, as well as the coal in the sides of the working initially occur with the sections (starting from the roof), whose shapes are close to slide prisms. Thereafter, this process encompasses the entire height of the sides of the working (fracture and slip surfaces 2 and 3 of the rock in Fig. i). This peculiarity of the failure and slip of rock and ...

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Origination and development mechanics of the Earth’s morphostructures. Part I: Etiology and evolution of the Patomsky crater

Stazhevskii

2011

J Min Sci

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Selecting the shape and bracing for excavations

Cited by 3 publications

References 6 publications

Origination and development mechanics of the Earth’s morphostructures. Part II: The nature of diatreme, karst and trappean formations, and the chicxulub crater origin

Origination and development mechanics of the Earth’s morphostructures. Part II: The nature of diatreme, karst and trappean formations, and the chicxulub crater origin

Deformation and failure of sedimentary rock around permanent and development mine workings

Origination and development mechanics of the Earth’s morphostructures. Part I: Etiology and evolution of the Patomsky crater

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