The horizontal load test on pressure-injected piles in damped subsiding Soils

¹ Mongolian National Technical University, dist. Songino hkairkhan, 11000 Ulaanbaatar, Mongolia
² Mongolian University of Science and Technology, Instituty of Technology Darkhan, 11000 Ulaanbaatar, Mongolia
³ Mongolian University of Science and Technology, School of Civil Engineering and Architecture, 11000 Ulaanbaatar, Mongolia
⁴ Saint-Petersburg State University of Architecture and Civil Engineering, 190005 Saint Petersburg, Russia

^* Corresponding author: nyamdorj@must.edu.mn

Abstract

In connection with the needs of the present, the question of the optimal design of building foundations, taking into account the regional characteristics of loess-like silty clay soils, common in Mongolia, becomes relevant. In recent years, in the Orkhon-Selenginsky region and especially in the Darkhan region, industrial and civil buildings and engineering structures are being actively built up and planned to regulate the problems of overpopulation and smoke in the city of Ulaanbaatar, Mongolia. The regularity of the process of changing the stress-strain state of loess-like subsidence soils of the base due to technogenic moistening is subject to the general theory of subsidence soil mechanics, but each region of the world has its own distinctive feature depending on territorial and climatic conditions. Settling clayey soils of Mongolia in their natural state have a relatively high content of water-soluble and slightly soluble carbonate and other salt compounds and, due to their cemented and crystallized structural bonds, they have relatively high mechanical properties, but the mechanical properties, due to the weakening of structural bonds during soaking, sharply decrease to a value of c =7.0…10.2 kPa, φ=16….÷20^°, E=3.5…4.5 MPa and subsidence begins depending on the type of soil at pressure Р=0,15 MPA and W= ( 6.7…8.6)% or W_sat, while the relative subsidence index is ε_sl>0.01. At pressure Р=0,2MPa and W=(6.1…7.6)%, subsidence begins, and at pressure Р=0.25MPa and W=(5.2…6.9)% drawdown begins. These moisture values are calculated respectively at the given pressures as the initial settling moisture W_sl. This article discusses the results of field tests of bored piles for a horizontal load, taking into account the moistening of the subsidence soil of the foundation of buildings and structures.