


Том 54, № 3 (2017)
- Год: 2017
- Статей: 12
- URL: https://journals.rcsi.science/0038-0741/issue/view/15194
Soil Mechanics
On the Calculation of Bored Piles Under Axial Compressive Loads in Rocky Soils
Аннотация
The behavior of single, reinforced-concrete, bored piles in solid rock is studied. Such a foundation can be used to transfer load from surface structures and buildings through a layer of weak soils to stronger underlying hard rock. A method is proposed for calculating piles under vertical loads taking account of the particulars of the changes in the stress-strain state of the system 'pile-rock' under compressive loads.



Evaluation of Maintained Load Test (MLT) and Pile Driving Analyzer (PDA) in Measuring Bearing Capacity of Driven Reinforced Concrete Piles
Аннотация
Results of several full scale RC (reinforced concrete) pile load tests were studied and analyzed to create a comparison between the MLT (maintained load test) and PDA (pile driving analyzer) methods. The ultimate pile capacities derived from analysis of PDA were consistently higher than results from the MLT. A coefficient of 0.9 or a 10% reduction is suggested to be applied to values derived from PDA. It is also observed that the longer the time interval, the greater the shaft friction contribution is towards the pile capacity.



Inclination Factors for Strip Footings on Non-Homogeneous Clay
Аннотация
In offshore industry, foundations are subjected to vertical and horizontal loads due to the self-weight and wind or wave forces, and they are founded on non-homogeneous deposits where the strength increases with depth. This paper aims to evaluate the inclination factor through the study of the undrained bearing capacity of strip footings on non-homogeneous clay under inclined loading. An expression of the inclination factor is proposed.



Buckling Analysis of an Axially Loaded Slender Pile Considering the Promotion Effect of Soil Pressure
Аннотация
Axially loaded slender piles may buckle when they are embedded in soil with relatively low lateral resistance and founded on a relatively stiff stratum. The present study develops an analytical solution to predict the critical buckling load of slender piles considering the prevention and promotion effect of the surrounding soil. The solution adopting active and passive side soil pressures is based on Hooke's law. A series of parametric studies is carried out to investigate and quantify the soil promotion effect and the effects of the soil deformation modulus, pile slenderness, and pile lateral influence ratio on the critical buckling load.



Design
Investigation of the Behavior of Strip Foundations with Complex Configuration of the Base
Аннотация
The results of experimental studies of models of strip foundations with different angle of internal notches for determining the optimal shape of the foundation pad with broken contour of the edge zone are presented. A design solution for such foundations is proposed. New experimental data are obtained on the stress state of the sandy base of strip foundations in the entire range of loads.



Inverted-Cone Piles for Transport Constructions in Seasonally Freezing Soils
Аннотация
An alternative design is proposed with inverted-cone bored piles for foundations of transport tunnels in frost heaving clayey soils of the Urals and Siberia regions. The bearing capacity of the inverted-cone pile with a side incline of 5 degrees and that of the pile without a cone was calculated.



Technology and Work Production
The Influence of Bituminous Coating on Uplift Resistance of Short Pile Foundations in Sand
Аннотация
Bituminous coatings can be used to reduce negative skin friction on pile. The present study investigates the other applications and the effectiveness of heated coating withelastic and visco-elastic-plastic behavior on the skin friction at soil-pile interface. Aseries of small scale physical modeling tests of short pile foundations under pullout load was carried out to study the effects of adhesive coating materials on the short pile foundation interaction. The results indicated that heated bituminous materials can significantly affect the pull-out capacity of short pile foundations.



Effect of Grain Composition and Porosity of Sand on the Possibility of Penetration of Cement Particles
Аннотация
The question of the distribution of pores in sand is examined. The relation between pore size and grain (granulometric) composition of Portland cement and cement from the Mikrodur Company is studied. The possibility of qualitative injection of sand is investigated. This same method can be used in other cohesionless soils: pebble-gravel soil and rock.



Technological Control of Permafrost Soil Characteristics in Roadbeds
Аннотация
It is shown that the physical-mechanical and thermal-moisture characteristics of high-temperature permafrost soils under process loads are interrelated. It is shown that technological process control for the purpose of increasing the carrying capacity of the base of geotechnical structures during the construction period is expedient.



Construction Experience
Large Oil Tank Settlement and Tilt During Hydraulic Testing
Аннотация
An example of the development of settlement and inadmissible tilt of an oil tank during hydraulic testing is presented. Data from engineering and geological research as well as a combined numerical calculation of the base and foundation by the finite-element method did not permit predicting the considerable tilt of the tank during hydraulic testing.



Construction on Permafrost
Reliability and Safety of the Foundations of Buildings and Structures on Permafrost
Аннотация
The reasons for the increase in accidents and the reduction of the safety of buildings and structures built on permafrost in the last 25 years are reviewed and analyzed. Measures to ensure increased reliability and reduction of accident risks in construction in permafrost areas are proposed.



Experimental Investigations
Experimental Investigation of Rapid Stabilization of Soft Clay Soils Using Chemical Admixtures
Аннотация
The rapid treatment of soft soil foundation is one of the main ways to solve problems associated with road construction. This study was conducted to determine the most effective stabilizer to increase the strength of wet and soft clay soils within 72 hours for rapid road construction. Extra admixtures are added to accelerate the reactions of cement and improve the stabilization effect. Using the unconfined compressive strength test (UCS), the effectiveness of admixtures was compared with that of a common cement-based binder. The results show that the addition of extra admixtures could rapidly improve the early strength of cement stabilized soils.


