Stress-strain State of Foundation Soil during Injection of Cement-sand Mortar in Hydrofracturing

   The relevance of the study is due to the need to improve the efficiency and quality of the injection process of cement-sand mortar during foundation soil strengthening.

   The use of a check valve and a clamping device allows achieving more uniform and stable filling of voids and cavities in the ground. Modern conditions of construction and reconstruction of facilities place increased demands on technologies for foundation soil strengthening, especially weak soils, where injection methods show insufficient effectiveness. Geotechnical monitoring based on computational software systems help to assess the stress-strain state of soil during injection. The applied approach allows not only to increase the injection efficiency but also to provide a more precise prediction of the soil behavior after strengthening, which is especially important in building design and operation.

   Purpose: The purpose of this work is to improve and commercially test injection of cement-sand mortar during foundation soil strengthening, including the use of a check valve and a clamping device.

   Research findings: It is shown that the stress-strain state of soil grows after strengthening. Calculated and real deformation of foundations decreases by 12 times, and stresses in the soil increase from 450 to 850 kN/m². The change in the pumping pressure of the mortar over time confirm its dependence on physical and mechanical properties of soil, which made it possible to more accurately regulate the injection process. Soil creep affects the stress-strain state of the foundation soil during injection of the reinforcing mortar and requires special attention when strengthening the foundation soil of buildings. It is important to note that stress relaxation after injection depends only on the pressure and physical and mechanical properties of the soil and is V = const.

1. Prokopov, A., Prokopova, M., Rubtsova, Y. The Experience of Strengthening Subsidence of the Soil under the Existing Building in the City of Rostov-on-Don. MATEC Web of Conferences. 2017; 106: 2001. DOI: 10.1051/matecconf/201710602001

2. Sinica, I.V., Ermolovich, E.A., Yacynyak, S.D. Forecast of the Cleaning Impact on the Stress-strain State of Soil near the Air Feeding Shaft. Izvestiya TulGU. Nauki o Zemle. 2023; 2: 18–431. (In Russian)

3. Kulibaba, S.B., Fedorov, E.V. Redistribution of Maximum Vertical Strain of the Mountain Range during Mining. Izvestiya TulGU. Nauki o Zemle. 2022; 1: 303–316. EDN: XJNDXG (In Russian)

4. Rachkov, D., Volosyuk, D., Pronozin, Y., Bartolomej, L. Experience of Strengthening the Soil Base with Parallel Lifting of the Foundation Structure. E3S Web of Conferences. 2022; 371: 02011.

5. Zbickaya, V.V., Psyuk, V.V. Justification of Boron Injection Technology in Foundation Soil Strengthening of Construction Facilities. Sbornik nauchnykh trudov DonGTI. 2022; 71(28): 113–118. DOI: 10.1051/e3sconf/202337102011 EDN: XNSPCZ In Russian)

6. Kharchenko, A.I., Khozin, V.G., Kharchenko, I.Ya., Piskunov, A.A. Application of Geopolymer Binders for Soil Compaction and Strengthening in Geoengineering. Ekspert: teoriya i praktika. 2023; 23(4): 133–139. DOI: 10.51608/26867818_2023_4_133. EDN: DGUYDO (In Russian)

7. Shakirov, I.F., Vilkova, A.O. Investigation of Soils Reinforced by Fine Cement Injection. Chronos: estestvennye i tekhnicheskie nauki. 2020; 5(33): 15–17. EDN: PBVPMD (In Russian)

8. Wintercorn, H.F., Pamukcu, S. Soil Stabilization and Grouting. Foundation Engineering Handbook, 2^nd edn. H.-Y. Fang, Ed. New York: Van Nostrend Reindhold, 1991. Pp. 317–378.

9. Bartolomey, L.A., Bogomolova, O.A., Geydt, V.D., Heydt, A.V. Computer Simulation of the Limiting State of the Base of the Slab Foundation, Taking into Account the Rigidity of the Above-Foundation Structure. Construction and Geotechnics. 2023; 14(3): 92–106. DOI: 10.15593/2224-9826/2023.3.09

10. Prokopov, A., Prokopova, M., Rubtsova, Ya. The Experience of Strengthening Subsidence of the Soil under the Existing Building in the City of Rostov-on-Don. MATEC Web of Conferences. 2017; 106: 02001. DOI: 10.1051/matecconf/201710602001

11. Koloshina, G., Prokopova, M., Tkacheva, K. Mathematical Modeling of the Stress-strain State of a Soil during the Construction of the Underground Part of Unique Buildings. Engineering and Digital Education. 2022; 2647: 60025. DOI: 10.1063/5.0104214. EDN: PAZJLV

12. Vlasov, M.A., Gerasimov, O.V., Prostov, S.M. Correction of Non-uniform Foundation Setting of the Mine Ventilation System. Vestnik Kuzbasskogo gosudarstvennogo tekhnicheskogo universiteta. 2025; 4(170): 5–17. DOI: 10.26730/1999-4125-2025-4-5-17 DOI: 10.26730/1999-4125-2025-4-5-17 (In Russian)

13. Vlasov, M.A., Gerasimov, O.V., Prostov, S.M. Prevention of Dangerous Foundation Soil Strain of the Ventilation System using a Geomechanical Model. Vestnik Kuzbasskogo gosudarstvennogo tekhnicheskogo universiteta. 2025; 4(170): 18–31. DOI: 10.26730/1999-4125-2025-4-18-31 (In Russian)

14. Tsvetkov, A.B., Pavlova, L.D., Fryanov, V.N. Numerical Simulation of Geomechanical State of Coal Massif in the Vicinity of Underground Workings in the Superimposed Seams. IOP Conference Series: Earth and Environmental Science. 2017; 84: 1–6. DOI: 10.1088/1755-1315/84/1/012005

15. Druz', R.A., Korytov, A.S., Protasova, A.V., Zhgilev, A.P. Analysis of Geomechanical Modeling Results of the Surface Displacement of Coal Quarry. Izvestiya TulGU. Nauki o Zemle. 2023; 3: 415–425. EDN: FDHITQ (In Russian)

16. Vlasov, M.A., Nikulin, N.Yu., Gerasimov, O.V., Petukhov, A.A. Soil Creep in Building Foundation Strengthening on Experimental Site in Tomsk. Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta – Journal of Construction and Architecture. 2026; 28 (1): 192–206. doi: 10.31675/1607-1859-2026-28-1-192-206 (In Russian)