The paper provides information about improvement of the weak clay soil with geotextile encased stone columns. The paper presents materials about the relevance of this technology for applying in Perm region of Russia. The article presents an overview and analysis of existing experimental studies on the subject, which allows identifying the area of the current study which aim is applying this technology to improve the weak bases of foundations of buildings and structures in geological condition of Perm region. Also paper considers the problem of estimating of deformations of improves soil base. Experimental studies consist of tests with use of triaxle equipment and stamp tests of big-scale models of geotextile encased stone columns. The conclusions about the effectiveness of geotextile encased stone columns were made on base of the results of experimental studies and analysis of existing materials. Also paper presents areas of possible cost-effective application of technology and the results of numerical simulation of test cases with using the finite element method.