The effect of antifreeze reagent on seasonal frozen soils

The design, construction, and maintenance of pile foundations are dependent on special weather conditions in Northern and Central part of Kazakhstan. The winter months in these areas are very long which starts from November to March and the air temperature usually reaches – 40-50°C. These circumstances lead to the seasonal freezing ground, special physical behavior of soil, physical properties of construction materials. The main problem of pile driving in winter is frozen ground which is difficult to excavate and driving. Moreover, the Static Load Tests for estimating the bearing capacity of pile foundations do not show accurate records in frozen soil. To solve the problems mentioned above, a special antifreeze composition has been developed and established its protective effect against soil freezing in winter. The implementation of the proposed method leads to a high productivity of driving reinforced concrete piles without the risk of their destruction. This eliminates the need for additional drilling works and more powerful and expensive rock drills, if the soil is protected from freezing. According to a special formula, the optimal mass of antifreeze is calculated, which allows protecting the soil without harming not only the soil, but also the structure of the concrete pile and the environment. During the static load test, piles driven into soil that had been covered with antifreeze has showed more accurate bearing capacity data. Scientific and experimental studies have established that antifreeze reduces the compressibility of frozen soil

Heat and Mass Transfer by Vapour in Freezing Soils

This paper is an extended version of our paper published in Cryosphere Transformation & Geotechnical Safety ‘21, Salekhard, Russia, 8–12 November 2021; pp. 366–369.Copyright: © 2022 by the authors. Vapour mass transfer is often underestimated when designing the bases for structures in frost susceptible soils. Intensive and long-term vapour transport may lead to excessive frost heaving and associated issues. A vapour transport model and the algorithm of its calculation is presented in this study based on the results of experimental freeze–thaw cycles of nine soil samples with varied density. The temperature field distribution, air voids volume and the energy comprising latent heat for the phase transition and heat extracted during the temperature drop are the main parameters for determining the vapour velocity and the amount of ice formed. According to the results, the average speed of vapour transport in frozen soils was about 0.4 m/h. The amount of ice built in 1 h during uniaxial freezing due to the saturated vapour pressure difference was 1.64 × 10−5–3.6 × 10−⁵ g/h in loose samples and 1.41 × 10−⁶ g/h to 5.61 × 10−⁷ g/h in dense samples of 10 cm diameter and 10 cm high sections. The results show that vapour mass transfer can increase the risk of ice growth and related problems.Funding: This research received no external funding

Model and field tests of drilled displacement system piles

Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) piles are two popular techniques used for building pile foundations that offer advantages over traditional pile systems, including improved load-carrying capacity, reduced installation time, and less spoil generation. This article presents laboratory-scaled model tests conducted on model piles installed using the Drilled Displacement System (DDS) and Continuous Flight Auger (CFA) technologies on a test tank setup filled with soil. Model piles considering a scaling factor of 1/20 with a diameter of 20 mm and a length of 300 mm were adopted for the study. Static loading is applied to the model piles and the corresponding displacements are measured during each loading phase. The results of the analysis were compared for load-settlement curves and ultimate bearing capacity estimates for both DDS and CFA piles. Based on the study, the DDS piles were observed to perform well in terms of load-carrying capacity compared to the CFA piles. Further, full-scale field tests under static load conditions were carried out on DDS-drilled piles of diameter 400 mm and length 6 m. The load-settlement response from the field test shows good agreement with the model tests. Overall, the results of the study provide valuable insights into the behavior and performance of DDS piles that can be used to optimize their design and installation in different soil types

Estimating the Driven Pile Capacities for COF Project in West Kazakhstan

[[abstract]]This paper presents estimations of bearing capacities of precast concrete joint piles at two construction sites in the regions of Port Prorva located in Western Kazakhstan. The capacities of the piles were predicted using the static pile load test data with the conventional interpretation methods. The results were compared to those from APILE analyses, analytical calculations based on the Kazakhstani standard method, and the pile driving analyzer. It was shown that the highest pile capacities were obtained from the Chin interpretation and Decourt extrapolation methods. The results from De Beer, Davisson, and Fuller and Hoy interpretation methods were found to be similar. The result from the Butler and Hoy interpretation method was similar to the ones obtained from pile driving analyzer and APILE analyses. The pile capacity obtained by the Kazakhstani standard method was found slightly higher, though it is applicable for estimating ultimate pile capacities. The yield capacity of the piles was determined under working loads. The methods used in the paper can also serve as practical guidelines to assess the capacities of driven piles installed in the field.[[notice]]補正完

Investigation of Interaction of Piles at New Cargo Sea Transportation Route and LRT Projects with Problematic Soils of Kazakhstan

[[abstract]]Two transportation megaprojects in Kazakhstan are considered. The first of these is the cargo offloading facility (COF) that was built on the northeastern shore of the Caspian Sea as part of the New Cargo Sea Transportation Route. The second project is the Light Railway Transport (LRT) public transportation system that was built in the capital city of Nur-Sultan. Due to problematic foundation soils, both of these larger projects employed piled foundations. This paper discusses the field investigations that were performed to quantify the performance of piles driven in the aforementioned soils so as to determine the pile bearing capacities using analytical interpretation techniques.[[notice]]補正完

FEATURES OF LABORATORY TESTING METHODS OF CLAYEY SOILS

The article compares the results of laboratory tests of dispersed soils to determine their strength characteristics. For this purpose, soils were tested on devices with three-axis compression and single-plane cut. In calculations for clay and sandy soils, indicators of their strength properties are used, which include such characteristics as the angle of internal friction φ and specific adhesion c. Based on the results of this work, recommendations on the practical application of the obtained soil characteristics for the geo-information geotechnical database of Astana were compiled