scholarly journals Research of perimeter reinforcement of the ground base by cement-sand mortar injection

2015 ◽  
Vol 2 (4) ◽  
pp. 151-156
Author(s):  
Леонид Нуждин ◽  
Leonid Nuzhdin ◽  
Матвей Нуждин ◽  
Matvey Nuzhdin

The article analyzes the results of a series of full-scale experiments for studying consolidation of foundations by perimeter reinforcement of the soil by rigid incompressible irregularly shaped inclusions. The experiments modeled consolidation of a shallow soil foundation base by directed high-pressure injection of mobile cement and sand mixtures. Generalization and analysis of the results of several dozens of laboratory experiments allowed to establish approaches to setting rational parameters of perimeter reinforcement of soil foundations by creation of rigid incompressible inclusions using injection of mobile cement-sand mixtures.

2021 ◽  
Author(s):  
Long Liu ◽  
Tianyang Dai ◽  
Qian Xiong ◽  
Yuehua Qian ◽  
Bo Liu

Abstract With increasingly stringent emissions limitation of greenhouse gas and atmospheric pollutants for ship, the direct injection of natural gas on the cylinder head with high-pressure injection is an effective method to make a high power output and decrease harmful gas emissions in marine natural gas dual fuel engines. However, the effects on mixing characteristics of high-pressure natural gas underexpanded jet have not been fully understood. Especially, the injection pressure is up to 30 MPa with large injection quantity and critical surrounding gas conditions for the low-speed two-stroke marine engine. Therefore, this research is focused on the flow and mixing process of the natural gas jet with high-pressure injection under the in-cylinder conditions of low-speed two-stroke marine engine. The gas jet penetration, the distribution of velocity and density, the equivalence ratio and air entrainment have been analyzed under different nozzle hole diameters by numerical simulation. The effects of surrounding gas conditions including pressure, temperature and swirl ratio on air entrainment and equivalence ratio distribution were studied in detail. From the numerical simulation, it is found that the mixing characteristics of natural gas jet can be improved under in-cylinder conditions of higher ambient temperature and swirl ratio, which is relevant to the low-speed two-stroke marine engine.


1998 ◽  
Vol 47 (3) ◽  
pp. 995-997
Author(s):  
Goichi Okahara ◽  
Hiroshi Hokama ◽  
Kunihiko Uehara ◽  
Fuminori Kanaya

MTZ worldwide ◽  
2017 ◽  
Vol 78 (5) ◽  
pp. 50-57 ◽  
Author(s):  
Junmei Shi ◽  
Pablo Lopez Aguado ◽  
Noureddine Guerrassi ◽  
Gavin Dober

2019 ◽  
Vol 10 (3) ◽  
pp. 5-15
Author(s):  
M. L Nuzhdin

Often in construction practice there is a need to strengthen the pile foundation of buildings and structures. The traditional methods include the implementation of additional, as a rule, bored piles with the subsequent erection of a grillage incorporating them into operation. Often, this work has to be done in the conditions of dense urban development, in cramped rooms of the basement, etc., which leads to significant technological difficulties. One of the alternative ways to strengthen pile foundations is the method of high-pressure group injection, which consists in injecting a movable cement-sand mortar into the soil under pressure that exceeds its structural strength. As a result, after its hardening, solid injection bodies are formed at the base, reinforcing the soil base. The article describes the results of experiments to assess the impact of the layout of hard inclusions on the deformability of the soil foundation of the pile foundation model. The experiments were carried out in a small soil tray, which was filled with medium-grained loose sand. The piles were modeled with metal rods, the pile grillage with a metal square stamp. The pile foundation model included 9 piles arranged in a square grid. As injection bodies, gravel grains of various sizes and shapes were used. The studies included 10 series of experiments (each experiment was repeated at least 3 times): the volume of the inclusions used, their sizes, the positioning step in the plan and in depth varied. As a result of the analysis of the performed experiments, conclusions were formulated regarding the purpose of the optimal layout of hard inclusions when strengthening the soil foundation of pile foundations by high-pressure injection of mobile cement-sand mixtures.


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