Justification of rheological test measurement parameters in incremental loading mode for rock salt

Stability of underground gas storages depends on proper design choices. Justification of the design choices requires reliable data on physical and mechanical properties of salt rock mass enclosing underground gas storages. Rock salt possesses pronounced rheological properties. In this connection, determination of rheological properties should be assumed as one of the top-priority tasks of geocontrol in construction and operation of underground gas storages. Very many experimental studies into rock creepage are known to date, including triaxial loading. Various mathematical models are available to predict behavior of materials under longterm deformation. Regulatory documents set the estimated period of operation for mining or construction facilities as 50 years, while the most creep tests last for not longer than 500 hours. The aim of this study is to reveal the behavioral patterns of rock salt in rheological tests of direct and incremental uniaxial and triaxial loading, with varying values and durations of load increments in rock salt samples of similar structure. The calculated rheological characteristics in the direct and incremental loading methods can be used to define the optimal approaches to estimation of rheological properties of salt rocks under uniaxial and triaxial loading. The experimental results made it possible to find the required incremental loading test parameters such that the rheological characteristics agree with the data of the direct loading tests.

Ageenko V.A. Justification of rheological test measurement parameters in incremental loading mode for rock salt. MIAB. Mining Inf. Anal. Bull. 2021;(4):113-123. [In Russ]. DOI: 10.25018/0236_1493_2021_4_0_113.

V.A. Ageenko, Graduate Student, e-mail: Valera.ageenko@mail.ru, National University of Science and Technology «MISiS», 119049, Moscow, Russia.

1. Nosikov A. V., Korotkov S. A., Tryavin E. Yu., Toropetskiy K. V., Mikhailov B. O., Borisov G. A. Investigation of creep of rock salts and application of well design in engineering calculations. Exposition Oil & Gas. 2018, no 7 (67), pp. 29—36. [In Russ].

2. Koshelev A. E. Obosnovanie i razrabotka metoda opredeleniya mekhanicheskikh svoystv kamennoy soli s uchetom nachal'nogo polya napryazheniy [Justification and development of a method for determining the mechanical properties of rock salt, taking into account the initial stress field], Candidate’s thesis, Moscow, 2013, 143 p.

3. Permyakov P. O., Solomentsev G. G., Garkushin P. K. The study of physical and mechanical properties, the process of deformation and destruction of salt rocks. Trudy VNIIGalurgii. 1974, Issue 67, pp. 108—119. [In Russ].

4. Tavostin M. N. The influence of the type of stress state on the rheological properties of rock salt. MIAB. Mining Inf. Anal. Bull. 2000, no 8, pp. 125—128. [In Russ].

5. Singh D. P. Long-tezm strength of rock. Colliezy Guazdian. 1977. Vol. 225. No 11. Pp. 861—866.

6. Wu C., Liu J., Zhou Z., Xu H., Wu F., Zhuo Y., Wang L. Study on creep properties of salt rock with impurities during triaxial creep test. Journal of Sichuan University (Engineering Science Edition). 2017. Vol. 49. Pp. 165—172.

7. Udartsev A. A., Pan'kov I. L. Creep study of red sylvinite at various lateral pressures. Problemy razrabotki mestorozhdeniy uglevodorodnykh i rudnykh poleznykh iskopaemykh. 2015, no 1, pp. 270—273. [In Russ].

8. Chtourou H., Guillot M., Gakwaya A.Modeling of the metal powder compaction process using the cap model. Part I. Experimental material characterization and validation. International Journal of Solids and Structures. 2002. Vol. 39. No 4. Pp. 1059–1075.

9. Wang R., Jiang Y., Yang C., Huang F., Wang Y. A nonlinear creep damage model of layered rock under unloading condition. Mathematical Problems in Engineering. 2018. Vol. 8. Article 8294390.

10. Zhou Z., Liu J., Wu F., Wang L., Zhuo Y., Liu W., Li J. Experimental study on creep properties of salt rock and mudstone from bedded salt rock gas storage. Journal of Sichuan University (Engineering Science Edition). 2016. Vol. 48. Pp. 100—106.

11. Liu B., Xu H., Dong L., Ma Y., Li K. A nonlinear rheological model of rock salt based on DS-dashpot under cyclic loading. Rock and Soil Mechanics. 2018. Vol. 39. Pp. 107—114.

12. Kuznetsov G. N. Mekhanicheskie svoystva gornykh porod [Mechanical properties of rocks], Moscow, Ugletekhizdat, 1947, 179 p.

13. Il'inov M. D., Kartashov Yu. M. The accelerated method for determining the rheological properties of rocks. Journal of Mining Institute. 2011, vol. 190, pp. 207—209. [In Russ].

14. Udartsev A. A., Bel'tyukov N. L. Investigation of creep of salt rocks of the Satimolskoye deposit of boron-potassium salts. Ctrategiya i protsessy osvoeniya georesursov: sbornik nauchnykh trudov. Vyp. 11 [Strategy and processes of development of geo-resources. Collection of scientific papers, Issue 11], Perm, GI UrO RAN, 2013, 298 p. [In Russ].

15. Konstantinov S. A., Vaulin I. B., Il'inov M. D. Some results of tests of samples of salt rocks on creep. Izvestiya vysshikh uchebnykh zavedeniy. Gornyy zhurnal. 2008, no 2, pp. 118—122. [In Russ].

16. Titov B. V. Issledovanie i razrabotka metoda opredeleniya dlitel'noy prochnosti solyanykh gornykh porod pri szhatii [Research and development of a method for determining the long-term strength of salt rocks under compression], Candidate’s thesis, Berezniki, 1983, 248 p.