scholarly journals Bearing capacity of deep bored piles

2020 ◽  
Vol 17 (3) ◽  
pp. 116-126
Author(s):  
Van Trong Le ◽  
Keyword(s):  
Statistical Processing ◽  
Field Tests ◽  
Side Surface ◽  
Soil Resistance ◽  
Underground Structures ◽  
Saint Petersburg ◽  
High Rise ◽  
Geological Conditions ◽  
Bored Piles ◽  
Technical Regulations

Modern technical regulations and design principles are limited by soil resistance on the side surface and under the point of bored piles up to 40 m. Meanwhile, the construction of high-rise buildings and underground structures requires the use of deeper bored piles. The author has set the task to determine the soil resistance for deep-bored piles by statistical processing of numerous results of field tests of bored piles and nonlinear extrapolation of soil resistance to a depth of 100 m in the geological conditions of Saint Petersburg.

Analysis of Bored Piles' Field Test Results

2019 ◽  
Vol 828 ◽  
pp. 194-201
Author(s):  
Lidia Kondratieva ◽  
Vladimir Konyushkov ◽  
Le Van Trong ◽  
Vladimir Kirillov
Keyword(s):  
Bearing Capacity ◽  
Deformation Modulus ◽  
Field Tests ◽  
Side Surface ◽  
Geometrical Parameters ◽  
Foundation Design ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Geological Conditions ◽  
Bored Piles

The purpose of the study is to establish accuracy of determining the load-bearing capacity of bored piles according to the method specified in Regulations 24.13330.2011 "Pile foundations". Relevance of the topic is determined by the following: the load-bearing capacity of a pile is a fundamental indicator affecting all subsequent activities related to foundation design, and accuracy of analytical solutions for complex engineering and geological conditions is highly questionable. Field tests of bored piles were carried out in engineering and geological conditions of Saint Petersburg with deformation modulus from 10 to 40 MPa at a load in the range from 1,000 to 6,300 kN, at achievement of absolute settlement of 40 mm. Piles with a diameter from 0.15 to 0.88 m and a length from 10 to 47 m were made using various technologies: using casing, using slurry, using a flight auger. Following the results of field tests, diagrams of load-bearing capacity of piles according to the material, depending on geometrical parameters and manufacturing techniques, diagrams of actual and designed load-bearing capacity of piles were plotted. Approximating functions to describe the dependences were obtained. According to the analysis of the results, it is possible to conclude that the load-bearing capacity of the bored pile during field tests is 1.4–1.7 times higher than the load-bearing capacity of the pile designed according to Regulations 24.13330.2011; the average share of the load-bearing capacity along the side surface of the pile was 65% and under the pile toe — 35%.

scholarly journals ANALYSIS OF THE FIELD TESTS RESULTS OF BORED CONICAL PILES UNDER THE ACTION OF VARIOUS TYPES OF LOADS

2018 ◽  
Vol 3 (3) ◽  
pp. 24-29
Author(s):  
Ирина Рыбникова ◽  
Irina Rybnikova ◽  
Александр Рыбников ◽  
Aleksandr Rybnikov
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Normal Component ◽  
Cone Angle ◽  
Field Tests ◽  
Side Surface ◽  
Test Results ◽  
Head Diameter ◽  
Cylindrical Piles ◽  
Bored Piles

One of the methods of improving the bearing capacity of bored piles is giving them a taper. The feature of these (wedge-type) piles is that under load they work "as a thrust" and transfer part of the load due to the normal component to the inclined side surface. Three sizes of tapered bored piles were tested, with the length of 4.5 m, head diameter 0.4; 0.5; 0.6 m and with cone angle 1o and 2,5o. The test results were compared with the test results of cylindrical piles, 4.5 m long, with head diameter 0.4 m and 0.6 m. It has been discovered that with the increasing cone angle, the bearing capacity of piles against the pressing load, especially the specific load capacity for 1 m3 of material, as compared to cylindrical piles, increases significantly. It has been determined that the larger is the diameter of the head of the pile, the higher is the bearing capacity against the horizontal load, and the bearing capacity against the pullout load is equal to the breakout force of a pile from the soil.

scholarly journals ANALYSIS OF THE RESULTS OF TENSOMETRIC STUDIES OF NATURAL BORED CONICAL PILES

2020 ◽  
pp. 44-55 ◽  
Author(s):  
I. Rybnikova ◽  
A. Rybnikov
Keyword(s):  
Bearing Capacity ◽  
Lateral Surface ◽  
Sandy Loam ◽  
Side Surface ◽  
Contact Stresses ◽  
Strain Gauges ◽  
Soil Resistance ◽  
Taper Angle ◽  
Different Types ◽  
Bored Piles

Four bored piles of two standard sizes with a length of 4,5 m, a diameter of heads of 0,4 and 0,6 m, a diameter of the lower end of 0,2 m with a taper angle of 1o20ʹ and 2o40ʹ, respectively, are studied. Two different types of piles are equipped with a height of four strain gauges, and two-ten bulldozers of five on each of the diagonal opposite sides. The soils on the experimental ground are composed of solid sandy loam. According to the measurements of strain gauges and load cell, plots of the distribution of forces and stresses in sections along the pile trunk, as well as plots of contact stresses along their lateral surface are constructed. The results of the research revealed that additional forces of soil repulsion along the inclined lateral surface during its sedimentation under load are significantly involved in the bearing capacity of bored conical piles. The proportion of soil resistance, depending on the angle of taper, is 34-49 % of the total bearing capacity, the resistance of the lower end – 17-23 %, friction on the side surface of the trunk-34-43 %. These data indicate the effectiveness of giving the trunks of bored piles up to 5 m even a slight taper in the range of 1,5 o ... 3,0 o.

scholarly journals Possibility of using RIT technology in the ground conditions of Vietnam

2020 ◽  
Vol 177 ◽  
pp. 02005
Author(s):  
Yury Kharin
Keyword(s):  
Soil Structure ◽  
High Efficiency ◽  
Field Tests ◽  
Physical And Mechanical Properties ◽  
Coastal Areas ◽  
Geological Conditions ◽  
Ground Conditions ◽  
Coastal Soils ◽  
Bored Piles ◽  
Water Saturated

The article compares engineering and geological conditions in the coastal areas of Vietnam and Tunisia. A sufficiently high similarity of soil structure and their physical and mechanical properties was noted. Both in Vietnam and in Tunisia, foundations for responsible buildings and structures are arranged on bored piles of the same length of 40-60 meters and a diameter of 600 to 1600 mm. The article provides examples of using super-piles of small-size RIT using recharge impulse technology in conditions of weak water-saturated coastal soils of Tunisia. The high efficiency and cost-effectiveness of the new recharge impulse technology were noted. The article presents photographic materials of the test stand for conducting field tests of piles, presents and analyzes the results of testing piles with vertical static load. The low precipitation of the tested piles and their high load-bearing capacity prove the promise of using super-piles of RIT in the conditions of weak soils of Tunisia and, consequently, in the coastal areas of Vietnam.

SARS-CoV-2 Herd Immunity of the Kyrgyz Population in 2021

2021 ◽  
Author(s):  
Anna Y. Popova ◽  
Omor T. Kasymov ◽  
Vyacheslav Y. Smolenski ◽  
Вячеслав Смирнов ◽  
Svetlana A. Egorova ◽  
...  
Keyword(s):  
Randomized Study ◽  
Herd Immunity ◽  
Statistical Processing ◽  
Cloud Service ◽  
Asymptomatic Infection ◽  
Enzyme Linked Immunosorbent Assay ◽  
Pasteur Institute ◽  
Cross Sectional ◽  
Saint Petersburg ◽  
Kyrgyz Population

Abstract Background. In the fight against coronavirus infection, an important direction is control of herd immunity to the pathogen. SARS-CoV-2 herd immunity is formed naturally as a result of manifest or asymptomatic infection, or artificially as a result of vaccination Aim: To assess the SARS-CoV-2 herd immunity status of the Kyrgyz population. Materials and methods. A cross-sectional, randomized study of SARS-CoV-2 herd immunity was carried out according to a program developed by Rospotrebnadzor, with the participation of the Saint Petersburg Pasteur Institute, taking into account WHO recommendations. In all study stages cloud service (internet) technologies were used. The ethics committees of the Preventive Medicine Association (Kyrgyzstan) and the Saint Petersburg Pasteur Institute (Russia) approved the study. A total of 9,471 volunteers were selected, representing 0.15% (95% CI 0.14-0.15) of the total population. They were randomized according to age and region. Antibodies (Abs) to the nucleocapsid antigen (Nag) were determined by enzyme-linked immunosorbent assay (ELISA) of volunteer blood plasma. For vaccinated individuals, Abs to the SARS-CoV-2 receptor-binding domain antigen (RBDag) were determined. Statistical processing of the results was carried out using Excel 2010 and other programs. Differences were designated as statistically significant at p<0.05. Results. The seroprevalence of the general population was 48.7% (95% CI 47.7-49.7), with a maximum in the group of '60-69 year old' (59.2% (56.6-61.7)) and a minimum in the group '1-17 y.o.' (32.7% (95 CI 29.4-36.1)). The largest proportion seropositive was found in the Chui region (51.3% (95% CI 47.9-54.8)). The lowest was in Osh city (38.1% (95 CI 32.6-43.9)). The maximum seropositivity was detected among healthcare workers (57.1% (95% CI 55.4-58.8); the minimum was noted among artists (38.6% (95% CI 26.0-52.4)). Asymptomatic SARS-CoV-2 positivity was 79.1% (96% CI 77.9-80.3). Vaccination with Sputnik V, EpiVacCorona, or Sinopharm formed comparable levels of immunity. Conclusions. The herd immunity to SARS-CoV-2 Nag is 48.75% (95% CI 47.7-49.7), and the overall immunity (Nag + RBDag) is 57%.

scholarly journals Soil Compaction Methods Development

2018 ◽  
Vol 7 (3.2) ◽  
pp. 636
Author(s):  
Tetyana Lvovska ◽  
Tetyana Lytvynenko ◽  
Alla Kariuk
Keyword(s):  
Soil Compaction ◽  
Clay Soil ◽  
Statistical Processing ◽  
Field Tests ◽  
Water Migration ◽  
Compacted Clay ◽  
Empirical Dependence ◽  
Compaction Test ◽  
Methods Development ◽  
Proctor Test

A process of soil compaction methods development including new authors’ methodology is described. The importance of soil compaction for engineering purposes is substantiated. Preconditions for Proctor compaction test appearance are highlighted. Proctor’s approach and suggestions for the degree of soil compaction assessing are analyzed. Soviet version of Proctor’s equipment and Modified Proctor compaction test are given. Principal differences between Proctor test, Standard compaction test and Modified Proctor test are presented. The problems and disadvantages of existent soil compaction tests are revealed. New authors’ physical experiment methodology for patterns establishment of water migration in subgrade embankment depth, in the capacity factors of what it is accepted: clay soil type (its number plasticity); moisture, at what the soil was compacted; soil skeleton density; embankment height; «rest» time after subgrade erection and before it’s operation is developed and realized. By laboratory and field tests water migration patterns in compacted subgrade soils depth are established. As a result of statistical processing of research results, the empirical dependence of compacted clay soil stabilized moisture is obtained. Empirical dependence parameter corresponds to maximum molecular moisture capacity at what it is advisable to do the subgrade clay soils multilayer consolidation for their long-term strength ensuring. 

scholarly journals High-rise construction in the Saint Petersburg agglomeration in 1703–1950s

2018 ◽  
Vol 33 ◽  
pp. 01008 ◽  
Author(s):  
Sergey Sementsov ◽  
Nadezhda Akulova ◽  
Severina Kurakina
Keyword(s):  
Visual Perception ◽  
Urban Planning ◽  
Spatial Perception ◽  
Altitude Range ◽  
City Development ◽  
Saint Petersburg ◽  
High Rise ◽  
Spatial System ◽  
The 1950S ◽  
The City

Regularities of high-rise construction (implemented projects and developments) in Saint Petersburg and the Saint Petersburg agglomeration since the foundation of the city in 1703 till the 1950s are considered. Based on these regularities, a single spatially developed system of vertical dominants is formed. High-rise construction in the city and its suburbs started in the 1710s and continues up to the present time. In the considered decades (1703–1950s), high-rise construction mostly performed urban-planning functions (with vertical and symbolic dominants), relying on patterns of the visual perception of man-made landscapes under development. Since the 1710s, the construction of vertical dominants (mainly temples, spires of towers, lighthouses, etc.) of five ranks (depending on the altitude range and in relation to the background development) was conducted in territories of the entire agglomeration. These dominants were arranged in landscapes of the city and suburbs with almost mathematically precise accuracy and according to special regulations. Such dominants obtained particular descriptive and silhouette characteristics in accordance with the conditions of spatial perception. In some periods of city development, attempts were made to create monuments (symbolic dominants) of specific height and include those in the spatial system of high-rise dominants as significant elements of the city silhouette.

scholarly journals Seismic Analysis Method for Underground Structure in Loess Area Based on the Modified Displacement-Based Method

2021 ◽  
Vol 11 (23) ◽  
pp. 11245
Author(s):  
Ruijie Zhang ◽  
Dan Ye ◽  
Jianting Zhou ◽  
Dengzhou Quan
Keyword(s):  
Design Research ◽  
Seismic Analysis ◽  
Design Method ◽  
Underground Structure ◽  
Time History ◽  
Shaking Table ◽  
Underground Structures ◽  
Loess Area ◽  
Geological Conditions ◽  
Displacement Based

At present, the seismic design research of underground structures in loess areas is lagging behind compared with practical engineering requirements. The selection of seismic calculation methods and parameters does not consider the influences of the special geological conditions in various regions, so their usefulness is limited. Based on the above problems, a modified displacement-based method (DBM) was proposed and its application was compared with the most commonly used methods of analysis (force-based design method, displacement-based design method, detailed equivalent static analysis numerical method, and the full dynamic time-history method). The results were also validated by considering data from shaking table tests conducted on a case study involving the underground Feitian Road subway station in Xi’an. The results show that compared with DBM, the average accuracy of the modified DBM technique is improved by 41.65%. The modified DBM offers good accuracy, simplicity in its model, a rapid analysis time, and easy convergence.

Field Tests of a Particulate Impaction Curtain on Emissions from a High-Rise Layer Barn

2007 ◽  
Vol 50 (5) ◽  
pp. 1795-1805 ◽  
Author(s):  
T. T. Lim ◽  
H. Sun ◽  
J.-Q. Ni ◽  
L. Zhao ◽  
C. A. Diehl ◽  
...  
Keyword(s):  
Field Tests ◽  
High Rise

scholarly journals Analysis on Loose Circle of Surrounding Rock of Large Deformation Soft-Rock Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Rui Wang ◽  
Yiyuan Liu ◽  
Xianghui Deng ◽  
Yu Zhang ◽  
Xiaodong Huang ◽  
...  
Keyword(s):  
Large Deformation ◽  
Theoretical Calculations ◽  
Rapid Development ◽  
Field Tests ◽  
Soft Rock ◽  
Strength Criterion ◽  
Surrounding Rock ◽  
Distribution Law ◽  
Geological Conditions ◽  
Rock Tunnel

With the rapid development of tunnel construction in China, deep buried and long tunnel projects are emerging in areas with complex engineering geological conditions and harsh environment, and thus large deformation of tunnels under conditions of high in situ stress and soft rock becomes increasingly prominent and endangers engineering safety. Therefore, it is of great significance to control the deformation and improve the stability of surrounding rock by analyzing the thickness and distribution law of loose circle according to the unique mechanical properties and failure mechanism of surrounding rock of large deformation soft-rock tunnel. Based on unified strength theory, this paper deduces the radius calculation formula of the loose circle by considering the influence of intermediate principal stress. Furthermore, the theoretical calculations and field tests of the loose circle in the typical sections of grade II and III deformation of Yuntunbao tunnel are carried out, and the thickness and distribution law of loose circle of surrounding rock of large deformation soft-rock tunnel is revealed. The results show that the formula based on the unified strength criterion is applicable for a large deformation tunnel in soft rock.

Sign in / Sign up

Export Citation Format

Share Document