СOMPARATIVE ANALYSIS OF METHODS DETERMINING BEARING CAPACITY OF DRILL-IMPACT MICROPILES

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Visnyk LNAU: Architecture and Farm Building 2017 №18: 52-56

СOMPARATIVE ANALYSIS OF METHODS DETERMINING BEARING CAPACITY OF DRILL-IMPACT MICROPILES

О. Hnatiuk, Ph.D.
М. Lapchuk, senior professor
Lviv National Agrarian University

https://doi.org/10.31734/architecture2017.18.052

Annotation

Four variants were selected for the study and evaluation of the bearing capacity of drill-impact reinforced concrete micropores: with different geometric characteristics with variable length and the presence of enlarged toe.

The drill-impact micropiles was made in the pre-manufactured auger drilling borehole by diameter of 175mm with enlargement of 175mm.

The field tests of micropiles were made by the method of using monotonously step-increasing vertical load in accordance with the requirements [5]. According to criterion (8.2.4 [5]), the carrying capacity of experimental natural samples of micropales was 95 and 105 kN (average value 100 kN) for MP-1 and MP-2; 158,33 kN for MP-3; 170,83 kN for MP-4 and 195,83 kN for MP-5.

Conclusions

1. Experimental and theoretical tests of the work of drill-impact reinforced concrete micropiles under the action of the vertical load were made and a comparative analysis of their results has been performed.

2. A comparative analysis of the results of determining the bearing capacity of micropile experimental samples by different methods showed that:

- Calculation according to the standards DBN B.2.1-10-2009 [1] provides an average of 30% of the bearing capacity and 30% of the possible loading relative to the data obtained from the results of experimental tests;

- Calculation using the program "Base" - 42 and 36%;

- Calculation according to the standards of SP 24.13330.2011 [2] – 36,5 and 31%;

- Calculation using the mathematical model [3] – 107,5 and 93%.

3. Thus, the most reliable data in determining the bearing capacity and possible loading is provided by a mathematical model, moreover in all cases the values of bearing capacity are overstated, other methods of calculation provide understated values, at that with the increase of the length of the pile, the reliability of the results increases.

Key words

drill-impact micropiles with enlarged toe, carrying capacity, comparison, analysis, different methods, geotechnical conditions

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Link

  1. DBN В.2.1-10-2009 "Bases and foundations of constructions. Basic design provisions" with a change of 1.2. Kyiv: Minregionbud of Ukraine, 2009. 96 p.
  2. SP 24.13330.2011 "Pile foundation" (updated version SNiP 2.02.03-85.). M., 2011. 90 p.
  3. Strembitsky B.Ya. Investigation of bearing capacity of drill-impact micropiles with enlarged toe in soils of different types [Text]: graduate work for Master's degree in Construction / Dublyany. Lviv NAU, 2016. 100 p.
  4. PP BKF Osnova. URL: http://pposnova.lviv.ua/buronabuvni.html.
  5. DSTU B V.2.1-27: 2010 Piles. Determination of bearing capacity based on the results of field tests / State Committee of Ukraine for Urban Development and Architecture. K.: Ukrahrbudinform., 2011. 14 p.
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