THE MECHANISM OF BLOCK COLLAPSE FORMATION UPON
ACTIVIZING THE DEEP LANDSLIDE IN TERMS OF DISSIPATIVE
STRUCTURES

© 2019 G. P. Postoev
Sergeev Institute of Environmental Geoscience, Russian Academy of Sciences,
Ulanskii per., 13, str. 2, Moscow, 101000 Russia
E-mail: opolzen@geoenv.ru

The paper considers the collapse mechanism in the back part of a new landslide block upon its separa­tion from the bedrock massif. It is shown that in the course of failure preparation, two blocks participate, i.e., the elements of dissipative structures that appear in the stress field of the bedrock landslide-prone massif. The study reviews the conditions of failure formation, stress distribution (in accordance with the Laplace solutions for axisymmetric thin-walled shells) inside the block and along its boundary surfaces (shells) when the massif limit state forms. The mechanism of block separation (discontinuity of the mas­sif) along the shell and specifics of soil deformation are also analyzed. The equilibrium in the head scarp massif is usually disturbed due to soil discontinuity forming along the earlier virtual circular-cylindrical shell of the first block, adjacent to the slope edge. In this case, the landslide block moves according to the detrusive mechanism. In addition to the ordinary process, the delapsive movement is also possible, with activating massif displacements in the lower part (washing-out, sliding, underworking of the lower part of the slope). This landslide activation favors to more intensely decreasing stresses in the back block shell in the head scarp massif, and consequently, to widening of the separation crack. At that moment, the in­fluence of the subsequent block becomes evident, as displacements take place along the frontal block shell and a failure massif forms between the specified boundaries. The examples of failure-blocks formation when the landslide process activates on the natural slopes and quarry slopes are given.

Keywords: dissipative structures, landslide block, failure, detrusion, delapsing, discontinuity.

DOI: https://doi.org/10.31857/S0869-78092019430-39

REFERENCES

1. Ivanov, I.P. Inzhenerno-geologicheskie issledovaniya v gornov dele [Engineering and geological research in mining]. Leningrad, Nedra, 1987, 255 p. (in Russian)

2. Instruktsiya po nablyudeniyam za deformatsiyami bortov, otkosov ustupov i otvalov na kar'erakh i razrabotke meropriyatii po obespecheniyu ikh ustoichivosti [Instruction on monitoring of pit edges, bank slopes and dumps deformations at the quarries and working out measuresd on providing their stability]. Leningrad, VNIMI, 1971, 188 p. (in Russian)

3. Kuznetzov, G.N., Ardashev, K.A., Filatova, N.A., et al. Metody i sredstva resheniya zadach gornoi geomekhaniki [Methods and means of solving problems in rock geomechanics]. Moscow, Nedra, 1987, 248 pp. (in Russian)

4. Postoev, G.P. Zakonomernosti gravitatsionnogo de- formirovaniya gruntovykh massivov [Regularities of gravitational deformation of soil massifs]. Geoe- kologiya, 2009, no. 6, pp. 534-543. (in Russian)

5. Postoev, G.P. Predel'noe sostoyanie i deformatsii gruntov v massive (opolzni, karstovye provaly, osadki gruntovykh osnovanii) [Limit state and deformation of soils in a massif (landslides, karst holes, settlings of ground foundations)]. Moscow, St. Petersburg, Nestor-Is- toriya Publ., 2013, 100 p. (in Russian)

6. Postoev, G.P. Dissipativnye struktury v gruntovom massive na primere formirovaniya glubokikh opolznei [Dissipative structures in a soil massif by the example of deep landslides formation]. Inzhenernaya geologiya, 2018, vol. 3, no. 3, pp. 54-61. (in Russian)

7. Tikhvinskii, I.O. Rekomendatsii po kolichestvennoi otsenke ustoichivosti opolznevykh sklonov [Recom-mendations for quantifying the landslide slopes stability]. Moscow, Stroyizdat, PNIIIS, 1984, 80 p. (in Russian)

8. Shakhunyants, G.M., Nechaev, B.I., Klevtsov, I.A., Pashchenko, B.V. Opyt bor'by s opolznyami na zheleznykh dorogakh SSSR [Experience in landslide control on the railways of the USSR]. Proceedings of TsNII. Moscow, Transzheldoriz- dat, 1961, no. 211, 184 p. (in Russian)

9. Bromhead, E.N., Ibsen, M.L. An overview of landslide problems in the British Isles with reference to geology, geography and conservation. Progress in Landslide Science, Part 1, chapter 2, Springer, 2007, pp. 13-25.

10. Prigogine, I., Nicolis, G. Selforganization in nonequilibrium systems: from dissipative structures to order through fluctuations. New York, J. Wiley & Sons, 1977.

11. Postoev, G.P., Kazeev, A.I. Theoretical solutions for an effective pit edge stability management. Proc. Int. multidisciplinary scientific geoconference SGEM, 2009, vol. 1, pp. 301-307.