Research and development support of the spacer system for the foundation pit constructed by the Moscow method

The article presents the results obtained during the research and development support for the construction of the foundation pit for a projected hotel near the Kursky railway station in Moscow using the truss spacer system fixed in the diaphragm wall. This construction technique, called the “Moscow method” ensures the gradual soil excavation between the pit walls along tiers reinforced by steel spacer trusses to be performed simultaneously with installation of floor slabs. The developed and approved at TsNIISK named after V.A. Kucherenko method for determining stresses (deformations) in elements of metal structures using mechanical strain gauges with a removable indicator was applied to monitor the construction of a unique structure. During the monitoring, emergency situations, requiring extra measures for eliminating the identified unacceptable stresses in the structures, were identified. The provided example demonstrates the research and development support to a prerequisite for the construction of unique buildings and structures.

Defining the rational installation position for the discharging unit of the bucketless rotary imple-ment in the trenching excavator

The increasing volumes of the earthworks performed by trenching excavators during the creation of the lengthy excavations in the soil for the pipelines of different sizes and other purposes create the need to improve the excavators, to create new highly productive machines of the fundamentally new construction. The goal of this work is to increase the performance of trenching excavators equipped with the bucketless rotary implement by improving the process of the soil discharging from the implement. To achieve this goal it is required to reveal the physical essence of the soil excavation by the bucketless rotary implement and based on the performed study to determine the rational installation position for the discharging unit of the bucketless rotor. Methodology. The scientific hypothesis is that discharging of the inner circular cavities of the bucketless rotor during the trench digging and the movement of the excavated soil to the side from the trench is possible by means of rational use of the flow header pressure of the soil that is being transported in the rotor from the excavation. The study is performed with analytical methods using basic principles of the theoretical mechanics, flowing medium statics, force analysis. Results. The study confirms the scientific hypothesis of the possibility to discharge the bucketless rotary implements of the trenching excavators by using the flow header pressure of the excavated soil that is transported by the rotor from the excavation, rational installation position of the discharging unit of the implement is defined. Originality. The scientific novelty of the study lays in the rationale and confirmation of the possi-bility to excavate and transport the soil from the excavation with the implements of the rotary trenching excavators with continuous flow and not with the separate portions. Practical value. Practical value lays in ensuring the 2-5 times performance increase of the excavation using the bucketless rotary implements.

Construction Cost for Soil Excavation (Cut and Fill) on-Site: Computer Based Program Analysis

Excavation is an important part of any construction project whereby removing earth to form cavity in the ground. This paper mainly focuses on cut and fill excavation by identify the cost of labor, material and equipment. Besides that, this paper aims to have better understanding on Bill of Quantity using coding. The method implemented for this study is using GNU Octave, version 6.2.0 and manual calculation to calculate the construction cost incurred during excavation process. Referring to the manual calculation, the overall cost obtained for the project is RM27352.15 whereas using GNU Octave software obtained for the project is RM27352.15. Thus, both GNU Octave software and manual calculation has zero percent difference. Octave is a computer programme that is designed for numerical computations and able to solve linear and nonlinear mathematical problems.

Soil Excavation pH level Modification

Territories are becoming new areas for conservationist replanting and forestation. Excavators are capable of producing entrainment s for new reservations. There lacks knowledge of soil conditions and methods of measurement of fertility of the developments. This research improves knowledge on the subject of excavations. To decide on territories which can be a best fit for excavations.

Study on the Earth Pressure during Sinking Stage of Super Large Caisson Foundation

End resistance is a dominant variable in the sinking process of super-sized caisson foundation, which is of great importance to the safe sinking of the caisson foundation. Based on soil excavation process of super large caisson foundation of the main tower of Changtai Yangtze River Bridge, the distribution characteristics and variation of earth pressure under the foot blade was analyzed using 3D finite element method at the first stage of soil excavation. Furthermore, the earth pressure was monitored in real time during soil excavation in order to analyze the influence of soil excavation process on the distribution of earth pressure. The analysis results of engineering practice showed that in the process of soil excavation from inner area to outer area, the end resistance of inner bulkhead and inner partition walls decreased, while the end resistance of outer bulkhead and outer partition walls gradually increased till the soil reached the failure state in the outer bulkhead area. The distribution characteristics and variation of the earth pressure can really reflect overall stress state of caisson foundation, which helps guide the safe sinking by soil excavation.

ANALYTICAL AND NUMERICAL METHODS FOR DETERMINING THE CARRYING CAPACITY OF A PILE BARETT ON WEAK SOILS IN DEEP PITS

The article provides an analysis of the bearing capacity of barrett piles in difficult geological conditions at a construction site in the city of Hanoi, Vietnam based on the results of analytical calculations according to Russian building codes, mathematical modeling and field full-scale tests. The paper describes a numerical test of a single barrette for Mohr-Coulomb and Hardening Soil models in the Midas GTS NX software package. The bearing capacity of a barrette in soft soils is also proposed to be determined by an analytical solution for calculating the settlement of a single pile, taking into account the unloading of the pit after soil excavation. The results of full-scale tests at the site of future construction, graphs of "load-settlement" of the barrette head from the applied vertical load and the general assessment of the bearing capacity of the barret pile by various methods are shown.

The Impact of Impervious Surface Expansion on Soil Organic Carbon: A Case Study of 0–300 cm Soil Layer in Guangzhou City

Empirical evidence shows that the expansion of impervious surface threatens soil organic carbon (SOC) sequestration in urbanized areas. However, the understanding of deep soil excavation due to the vertical expansion of impervious surface remains limited. According to the average soil excavation depth, we divided impervious surface into pavement (IS20), low-rise building (IS100) and high-rise building (IS300). Based on remote-sensing images and published SOC density data, we estimated the SOC storage and its response to the impervious surface expansion in the 0–300 cm soil depth in Guangzhou city, China. The results showed that the total SOC storage of the study area was 8.31 Tg, of which the top 100 cm layer contributed 44%. The impervious surface expansion to date (539.87 km2) resulted in 4.16 Tg SOC loss, of which the IS20, IS100 and IS300 contributed 26%, 58% and 16%, respectively. The excavation-induced SOC loss (kg/m2) of IS300 was 1.8 times that of IS100. However, at the residential scale, renovating an IS100 plot into an IS300 plot can substantially reduce SOC loss compared with farmland urbanization. The gains of organic carbon accumulation in more greenspace coverage may be offset by the loss in deep soil excavation for the construction of underground parking lots, suggesting a need to control the exploitation intensity of underground space and promote residential greening.