Wyniki wyszukiwania - Biblioteka Nauki

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Conditions of proper interaction of low-pressure injection piles (LIP) with structure and soil, carrying capacity of pile anchorage in foundation

100%

Pachla H.

Studia Geotechnica et Mechanica

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2016

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tom Vol. 38, nr 4

33--49

EN

The formation of a pile in the existing foundation and soil creates a new foundation construction which has a structure of foundation-pile-soil. This construction must be able to transfer loads from the foundation to the pile and from the pile to the soil. The pile structure has to transfer an imposed load. From the point of view of continuum mechanics determination of the capacity of such a system is preceded by the analysis of contact problem of three contact surfaces. Each of these surfaces is determined by different pairs of materials. The pair which creates a pile anchorage is a material from which the foundation is built (structure of stone and grout, brick and grout, concrete or reinforced concrete and grout. The pile structure is formed by grout and steel rebar. The pile formed in soil is created by a pair of grout and soil. What is important is that on contact surfaces the materials adhering to one another are subjected to different deformation types that are controlled by mechanical properties and geometry of these surfaces. In the paper, additional conditions that should be fulfilled for the foundation-pile-soil system to make load transfer from foundation to soil possible and safe are presented. The results of research done by the author on foundation-pile contact surface are discussed. The tests were targeted at verifying the bearing capacity of anchorage and deformation of piles made of grout and other materials from which foundations are built. The specimens were tested in tension and compression. The experiments were conducted on the amount specimens which is regarded as small sample to enable the statistical analysis of the results.

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Experimental verification of integrity of low-pressure injection piles structure – pile internal capacity

100%

Pachla H.

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tom Vol. 39, nr 4

77--85

EN

The idea of strengthening the foundation using injection piles lies in transferring loads from the foundation to the piles Anchorage in existing structure and formed in the soil. Such a system has to be able to transfer loads from the foundation to the pile and from the pile onto the soil. Pile structure often reinforced with steel element has to also be able to transfer such a loading. According to the rules of continuum mechanics, the bearing capacity of such a system and a deformation of its individual elements can be determined by way of an analysis of the contact problem of three interfaces. Each of these surfaces is determined by different couples of materials. Those surfaces create: pile-foundation anchorage, bonding between reinforcement and material from which the pile is formed and pilesoil interface. What is essential is that on the contact surfaces the deformation of materials which adhere to each other can vary and depends on the mechanical properties and geometry of these surfaces. Engineering practice and experimental research point out that the failure in such structures occurs at interfaces. The paper is concentrating on presenting the experiments on interaction between cement grout and various types of steel reinforcement. The tests were conducted on the special low pressure injection piles widely used to strengthen foundations of already existing structures of historical buildings due to the technology of formation and injection pressure.

3

Niskociśnieniowe pale iniekcyjne wyciągane z gruntu przy ograniczonej deformacji gruntu na powierzchni

75%

Pachla H.

Geoinżynieria : drogi, mosty, tunele

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2013

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tom nr 4

36-40

PL

Próba doświadczalnej weryﬁkacji przemieszczeń niskociśnieniowych pali iniekcyjnych w warunkach podnoszącego pal obciążenia osiowego z ograniczoną deformacją powierzchni gruntu przez siły równoważące obciążenie wyciągające pal.

EN

In this text, it was attempted to experimentally verify the movement of low-pressure injection piles in the conditions of lifting axial forces and limited ground surface modelling by forces balancing the lifting pressure of the pile. The examination was performed in a duly prepared experimental area. As it has become evident during the comparison of survey results of piles extracted on a loose ground surface and in case of limited ground surface modelling, the proposed technology of test load consisting of a system of self-balancing forces may act in this respect as an authoritative test. It seems however that due to the great discrepancies between research results, it will be necessary to perform more tests as regards the maximum power value.

4

Deformacja i nośność zakotwienia niskociśnieniowych pali iniekcyjnych w betonowym fundamencie przy obciążeniu wciskającym pal w grunt

63%

Pachla H.

Geoinżynieria : drogi, mosty, tunele

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2014

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tom nr 2

28-32

EN

The construction of proper anchoring is an essential precondition for an appropriate pile installation. Such anchorage must transfer at least the designed load capacity of the piles. Otherwise, the piles are useless. The presented research indicate the reasonableness of considering the anchorage bearing capacity on the design stage, as an important factor of their effective operation. This capacity should not be lower than the external bearing capacity of the pile, determined by the ground resistance.

PL

Istotnym warunkiem właściwej pracy pali jest skonstruowanie poprawnego ich zakotwienia w fundamencie. Zakotwienie to musi przenosić co najmniej obciążenie projektowe pali. Bez spełnienia tego warunku pale staja się bezużyteczne.

5

Niskociśnieniowe pale iniekcyjne poddane osiowemu obciążeniu cyklicznemu

63%

Pachla H.

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tom nr 1

34-39

PL

Szerokie zastosowanie fundamentów palowych przy posadawianiu konstrukcji inżynierskich oraz przy wzmacnianiu już istniejących fundamentów o tradycyjnym posadowieniu bezpośrednim, zdeterminowało konieczność pracy pali w różnych warunkach ich obciążenia.

EN

In view of extensive use of pile foundations for engineering structures and reinforcement of existing traditional shallow foundations, the piles are expected to perform in various load conditions. Regardless of the loads with fixed time, structures (such as wind turbines, abutments of bridges, road and railway viaducts and structures in areas prone to seismic or para-seismic risks) are subjected to repeated loads with various nature of individual cycles.

6

Warunki poprawnej współpracy niskociśnieniowych pali iniekcyjnych z konstrukcją i gruntem, zakotwienie pala w fundamencie

63%

Pachla H.

Geoinżynieria : drogi, mosty, tunele

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2016

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tom nr 2

34--38

PL

Wyniki prezentowanych badań wskazują na to, że w wielu przypadkach wykonawczych nośność zakotwienia pala w fundamencie może w sposób istotny wpływać na bezpieczne rozwiązanie projektowe. Zasadna zatem wydaje się konieczność wprowadzenia dodatkowych warunków projektowych.

EN

The results of presented studies indicate that in many construction cases the pile anchoring capacity can significantly affect safe design solutions. Therefore, it makes sense to formulate additional design criteria. In the light of the studies, an important issue is to propose a design-friendly computational model of contact problem solving which accounts for any slippage function.

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Niskociśnieniowe pale iniekcyjne wyciągane z gruntu

63%

Pachla H.

Geoinżynieria : drogi, mosty, tunele

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2013

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tom nr 3

30-33

PL

Niskociśnieniowe pale iniekcyjne znajdują szerokie zastosowanie w wielu konstrukcjach inżynierskich, w przypadkach gdy decydujące o stabilności konstrukcji jest jej zakotwienie w gruncie. Podczas projektowania istotne znaczenie ma poprawność modelu współpracy pala z otaczającym go gruntem w warunkach obciążenia, powodującego podnoszenie (wyciąganie) pala. W niniejszym tekście podjęto próbę doświadczalnej weryfikacji przemieszczeń niskociśnieniowych pali iniekcyjnych w warunkach podnoszącego pal obciążenia osiowego ze swobodną powierzchnią gruntu.

EN

Low-pressure injection piles are widely used in many engineering structures, where ground anchoring is of decisive importance. In the course of design it is important to ensure the correctness of the pile cooperation model with the surrounding ground in the situation of lifting pressure (pile pushing). In this text, it was attempted to experimentally verify the movement of low-pressure injection piles in the conditions of lifting axial forces and loose ground surface.

8

Kotwienie niskociśnieniowych pali iniekcyjnych wciskanych w grunt w fundamentach wykonanych z cegły

63%

Pachla H.

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tom nr 1

52-54

EN

Low-pressure injection piles are widely used to reinforce the foundation of existing constructions from various historical periods. The crucial element is the proper interaction between the foundation and the pile that transfers the burden from the foundation to lower ground layers. Tests have been carried out on samples made of modern solid brick on lime-cement mortar. They have proven the usefulness of the self-anchoring connection between the brick foundation and a low-pressure injection pile. The connection is broken by disrupting the foundation and knocking the pile out of it. From a designing perspective, the important aspect is the load-bearing capacity of the foundation against imposed positive deformation on the plane perpendicular to the pile axis.