Injection Pile Research Articles

Contribution for a root pile installation control approach using a digital odometer

A root pile is a form of injection pile (cast-in-place with pressure, with very distinct construction aspects from the known micropile type). During the mortar shaft development, these piles are inserted using distinct injection pressures of up to 500 kPa. Static load tests are typically used to control root piles, which can be an expensive and time-consuming testing procedure. Static load tests were performed on eight monitored piles with diameters of 350 and 410 mm to investigate root pile performance control during pile installation. This research presents a refined and developed alternative methodology for confirming root pile performance using a digital odometer attached to the drill rig’s rotatory head. The methodology consists of monitoring variables obtained during pile installation related to pile bearing capacity. Moreover, empirical equations with simple and relevant applications to estimate root pile bearing capacity during installation are proposed. The developed equations produced results consistent with the values obtained from static load testing on the test piles. Therefore, the results suggest that the proposed methodology is a viable alternative for root pile performance control.

Approaches to increase the load bearing capacity of bored injection piles

The issue of strengthening weak or overloaded bases is an important task for the development of underground space. This is especially true in the presence of alternating weak layers at the base. The paper considers a case from the geotechnical practice of strengthening the overloaded base of a reinforced concrete foundation plate of a 25-storey residential building under construction.Combined ground piles consisting of Get (type 1) ground concrete piles reinforced along the longitudinal axis with made drill-injection piles using electric discharge technology (EDT piles) are used as buried structures. This method of arrangement of a combined buried reinforced concrete structure is due to the need to increase the load-bearing capacity of the pile on the ground by two times or more

Experience in application of drilled injection piles for building and structure strengthening

The paper presents the experience of building and structure strengthening in Tyumen soil conditions which are often presented by a soft water saturated clay and sand layer of the quaternary period. All buildings mentioned in the paper had uneven settlements due to complex engineering and geological conditions and the wrong choice of foundation type. Thin drilled injection piles with a diameter of 200 mm were used for foundation strengthening. All the piles were installed on the solid soil base during the drilling process regardless of the depth of its location. No rules have so far been approved to calculate the bearing capacity of thin drilled injection piles. That was the reason for defining the drilled injection pile bearing capacity at every facility. The paper describes the methods and test results obtained in the study. It was found out that all piles had unexpectedly high bearing capacity. The paper also contains the results of geotechnical monitoring before and after base building strengthening by drilled injection piles which show the current decrease of settlements and the efficiency of this base strengthening method.

Foundations for light structures

Due to developments in soil mechanics, the price of foundations for ordinary structures has decreased to 5 to 10 per cent of the overall price of the building, but it still remains relatively high, sometimes exceeding 30 %. In Estonia, this issue has been relevant for the past years. The first solution was to use wedged piles under agricultural buildings (barns, storage units etc). As a result, the concrete content of foundations decreased 30 to 60 %, and the rate of steel use went up by 50 %. Currently the cooperation between wedged piles and grillage is being researched, with the objective of lowering the price of foundations. ln weak soils, 2-8 m injection piles have been used under private houses, holiday homes and storage structures, but one can save in the cost of foundations that way. Light structures and storage units have often been erected on screw piles (the steel pipe of the pile 100x100x6 filled with concrete, the pile end a steel sheet 15-20 mm thick and (depending on load bearing capacity) 25-60 cm in diameter. These piles can receive pressure as tension and if designed with the cooperation of piles and grillage in mind, the cost of foundations will decrease 50-60%. All of these solutions have been in use in Estonian silt and sands, the screw piles also in weak soils, where they stand on the dense intermediary layers alternating in weak soils.

STRENGTHENING OF THE FOUNDATIONS OF RENOVATED BUILDINGS WITH INJECTION PILES

The paper describes the technique of strengthening shallow foundations of reconstructed buildings using injection piles. First, the constructive solution of the existing foundations, the structural scheme of the building, as well as the loads transferred to the building structures before and after its reconstruction are established. At the same time, an assessment of the soil conditions of the construction site of the reconstructed building is carried out; a bearing soil layer is revealed for deepening the lower ends of injection piles. Based on the data obtained, the loading of the base of the foundations of the reconstructed building is assessed and the need for their reinforcement (or further operation without reinforcement) is established. In the case of strengthening the foundations of the building, the method of transferring the additional load to the injection piles is selected. Then their bearing capacity and design loads allowed on the piles are substantiated. The construction of foundations is carried out, taking into account their reinforcement with injection piles, which are hereinafter called combined. Verificationcalculations of the base of the combined foundations are performed for the firstand second groups of limit states. In accordance with the regulatory documents, strength calculations of the main structural elements of foundations are carried out, which are necessary to ensure their full operation, taking into account the reinforcement. At the finalstage, working documentation is developed to strengthen the foundations of the reconstructed building. The stages of the design of strengthening the foundations of reconstructed buildings using injection piles presented in the work allow to properly and consistently organize the work of specialists.

An approach to increasing the load-bearing capacity of drilled injection piles

The problem of strengthening weak or overloaded bases is an important objective of underground space development. It is especially urgent if there are alternating weak layers in the base. The paper presents a practical geotechnical case of strengthening the overloaded base of a reinforced concrete foundation plate for a 25-storey residential building under construction. Combined soil piles that consist of Jet (type 1) soil concrete piles reinforced along the longitudinal axis with drilled injection piles made by electric discharge technology (EDT piles) are used as buried structures. This method of arrangement of a combined buried reinforced concrete structure is conditioned by the need to increase the load-bearing capacity of a pile in soil by two or more times.

ASSESSMENT TO THE PILE BEARING CAPACITY OF INJECTION PILE BASED ON PILE DRIVING ANALYZER AND RE-INJECTION TEST RESULTS (CASE: EASTKAL PENAJAM PROJECT)

Injection piling method was used as the main pile driving method at the three warehouses in the Eastkal Penajam project, Kalimantan, Indonesia. The sub-soil compositions are dominated by clay and sandy soil with very soft to medium consistencies. By using injection pile equipment, it is possible to measure the pile bearing capacity from the loading gauge. Since the soil is dominated by clay, the friction capacity overtime will be improved. For that purpose, the piles were re-injected again after 3, 10, 11, and 25 days. To establish the forecasting expression of pile bearing capacity enhancement for other piles, non-linear regression analysis was performed. To verify the result, pile driving analyzer (PDA) test for selected piles was carried out. The results from PDA test were further analyzed by using both direct fields reading in the PDA data logger and the Case Pile Wave Analysis Program (CAPWAP). A linear regression analysis was carried out to complete the blank data due to the field measurement limitation. In addition to the obtained field data, theoretical analysis of pile bearing capacity with Luciano Decourt method is carried out. From the comparisons of all data, it can be concluded that re-injection pile method provides the highest safety factor followed by PDA test, CAPWAP analysis, and theoretical design calculation with Luciano Decourt method.

Method justification for calculating the final setting of injection pile in clay soil

Method of final setting calculation for a single injection hanging pile 3 to 5 m length in clay soils is proposed. The method is based on the separate work of the lower end and the lateral surface of the injection pile; it takes into account the linear and non-linear dependencies of its setting from external load. The method takes into account the stages of the well formation by the injector pressing, its radial expansion during the concrete injection, and the physical and mechanical characteristics improvement of the soil around the injection pile barrel at its construction stage. The obtained results are considered as an approach to solving a complex task of estimating the deformations of individual and strip foundations after their strengthening with injection piles under buildings reconstruction. It can be used to predict the buildings foundations setting under new construction.

Economic benefit analysis of low-level high vacuum compaction method from the perspective of low carbon

In order to discuss the superiorities of High Vacuum Drubbing Means (HVDM) in soft foundation treatment of roads, this paper takes the soft foundation treatment project of Wucheng Road in Wuwei County of Wanjiang City Belt in China as an example. By comparing and analyzing the economic benefit differences between HVDM method and traditional powder injection pile method in soft soil foundation treatment, the following conclusions are drawn: Low-level high-vacuum compaction method soft base processing method is better than traditional powder-jet pile method in soft foundation treatment. The method can better reduce the consumption of raw materials such as cement and stone, avoid the pollution of the social environment caused by cement production, shorten the construction period by about 50 % and save the direct labor cost. Compared with the traditional powder-sprayed pile method, total cost of the project can be saved by more than 30 % and the construction quality is controllable. The construction process is green and its social and economic benefits are remarkable.

Engineering Method of Calculating Injection Pile Settlement in Clayey Soils

An engineering method of calculating the ultimate settlement of a single hanging injection pile of length from 3 to 5 m in clayey soils, including weak soils, is proposed. The method takes into account the linear and nonlinear dependences of the settlement on the external load and is based on taking into account the operation of the bottom end and the lateral surface of the injection pile. The obtained results can be used to solve the complex problem of evaluating the deformations of individual and strip foundations after they are strengthened by injection piles in the reconstruction of buildings as well as new construction.

Experimental Verification of Integrity of Low-Pressure Injection Piles Structure – Pile Internal Capacity

Abstract 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.

Application of inclined injection piles as a means of seismic protection of slope

The using of inclined injection piles in an area with high seismic activity is described in this work with the purpose of their application in the construction of various facilities in seismic active areas. In this paper the authors define the possibility of their using for the stability of the slopes and slope construction in the earthquake conditions. The authors analyze sustainability slope both with the use of inclined injection piles and without them. They offer a methodology for determining the embedment of inclined injection piles into the thickness of slope.

Conditions of Proper Interaction of Low-Pressure Injection Piles (LIP) with Structure and Soil, Carrying Capacity of Pile Anchorage in Foundation

AbstractThe 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.

Результаты полевых исследованийвзаимодействия буроинъекционной сваи с контролируемым уширением в пылевато-глинистых грунтах пластичной консистенции

the paper discusses the results of in-situ tests for behavior of the drill injection pile with controlled widening at its end in pulverescent – clay foundation soil of flexible consistency carried out at an experimental site in Tyumen. The results make of possible to determine the radius of the consolidation zone, its tress – strain condition
 and physical – mechanical properties. He soil bed in its active zone changed in the area of the drill – injection pile. The comparative analysis has been carried out to reveal the behavior of the drill – injection pile with controlled widening and without it with single and repeated injection grout under vertical static loading.

УСИЛЕНИЕ ФУНДАМЕНТОВ АДМИНИСТРАТИВНО – ТОРГОВОГО ЗДАНИЯ ПРИ ПОНИЖЕНИИ ОТМЕТОК ПОЛА ПОДВАЛА

Reconstruction of cellar part of the two-storeyed brick building in Tomsk is considered. The main objectives of reconstruction included deepening of a floor of the cellar with 2,5 to 4,5 m with the construction in internal bearing walls of apertures width to 3,5m. Decisions on strengthening of the foundations which provided a reorganization of the rubble tape foundations in concrete with use of injection piles are developed. Thus the mark of a sole of the new foundation is arranged 1,4 m below than a sole of the existing foundation

Развитие метода оценки загружения отдельных фундаментов для их усиления в глинистых грунтах с использованием инъекционных свай

Развитие метода оценки загружения отдельных фундаментов для их усиления в глинистых грунтах с использованием инъекционных свай

Опыт усиления фундаментов реконструируемых зданий инъекционными сваями

Опыт усиления фундаментов реконструируемых зданий инъекционными сваями

Reliability Method and its Standard of the Composite Foundation Bearing Capacity

The general reliability analysis method of composite foundation bearing capacity was established with the example of cement injection pile, its limit state equation and the optimize method was presented, and the standard of reliability index was also proposed according to the corresponding demand of architectural structure. It indicate that the method is reasonable, convenient to calculation and can be popularized in the whole geotechnical engineering.

Reinforcement of foundations as part of reconstruction of the stebnikov potash plant

The effectiveness of using drilled injection piles to reinforce foundations while reconstructing an operating plant without shutting it down was shown.

Foundation underpinning by means of piles

Jacked piles are more economical than bored—injection piles both in labor and material costs. Unlike bored—injection piles, they are installed with prestressing. It is advisable to place the jacked plies at distances of 5 m from each other, and to use reinforced concrete for the wall beams.