THE FORECAST OF LONG-TERM SETTLEMENT OF THE PILE ON SANDSTONES AND CLAYSTONES OF THE PERMIAN AGE

Abstract

In the article the problem of ensuring the long-term settlement of single piles on claystones and sandstones are reviewed. Incorrect assessment of stabilized settlement of pile foundation can lead to an emergency situation. At the present time for prediction of foundation settlement is widely used finite element method, implemented in a variety of software systems. The aim of the study was to select the optimal model in the software package Plaxis 3D to forecast settlement of driven and bored piles on claystones and sandstones. The authors solved the following tasks: 1) review of the knowledge of long-term settlement of single piles and pile foundations on claystonese and sandstones is performed; 2) the technique is described and numerical experiments are performed in the software package Plaxis 3D for modeling the settlement of a single driven pile and bored pile on claystones and sandstones with varying degrees of weathering; 3) comparison of the results of numerical experiments with long-term field tests of piles on claystones and sandstones is performed; 4) findings from the study are formulated. Numerical experiments of modeling in the software package Plaxis 3D work of driven piles on claystones and sandstones showed that the introduction of soil compaction zones around the driven pile into the calculation scheme makes it possible to obtain close values to long-term settlement of full-scale piles. The authors recommend using the Hardening soil model to predict the work of a driven pile on claystones and sandstones and the Linear-Elastic model to simulate the work of a bored pile on claystones and sandstones. For highly weathered claystones and sandstones soil models need to be corrected for numerical calculations in Plaxis 3D, since the use of the Hardening soil and Linear-Elastic models showed underestimated settlement values in relation to field tests of driven piles.