In general state, soil improvement is defined as change in any properties of soil in order to improve the performance of soil that actually lead to improvement of problematic soil weaknesses in bearing capacity, compressibility, settlement, expansion, etc.
In the first step, before any measure for design and construction of civil structures, it is necessary to evaluate properties of soil and geology in considered area and if its resistance is not enough for construction, improvement of soil under foundation should be done.
Soil improvement is done using different modern technics, depending on conditions and type of soil, construction type, environmental factors, regional conditions, construction limitations, importance of project, allowed time to complete the project and economic issues.
Soil improvement methods, depending on conditions, may be use as a temporary process for construction of facilities or as a permanent measure in order to improve physical and mechanical parameters of soil.
Use of new soil improvement methods in different civil projects, with reliance on evolution of geotechnical engineering knowledge and appearance of technology in civil engineering has been possible in recent years.
ASACO engineering company is one of the successful companies in soil improvement field through the country which is able to design and construction of structure strengthening and soil improvement projects using experienced experts and according to the latest standards and the most modern methods in the world.
The reasons of soil improvement necessity
According to this fact that in every structure and civil project, the load is applied to soil from the upper structure, soil is known as one of the most important materials in civil engineering. In recent years, with the population growth, the need of construction has been increased in big towns. On the other hand, the shortage of natural resources in order to replace weak materials with qualified materials to supply design requirements has become a problem. ignoring the weakness of mechanical properties of soil in construction stage, provides numerous difficulties such as structure and roadway destruction due to subsidence and landslide, insecure excavations, settlement and cracking in industrial structures, collapse of transmission towers due to flood, etc. in these situations improvement of existing resources is a practical and economic solution to overcome these problems. Also, in many big projects such as tunneling, road construction, dams and…it is very likely to encounter with weak soils and as a result, the construction of project is impossible without soil improvement.
In summary, existence of unsuitable soil in construction site, lack of enough space to construction and lower cost of soil improvement in comparison with replacing it with qualified soil, are the primary and mainly reasons for using soil improvement technics. Also, the results of soil improvement in deep excavation stability has evaluated very desirable.
Soil improvement purposes
generally, the purpose of soil improvement, is improvement of soil properties in order to increase bearing capacity and reduce expected settlements and changing a weak mass soil into a new resistant structure to withstand applied loads, forces and design requirements. Because in most cases, the soil in normal mode is unable to meet design requirements. In general, soil improvement purposes are according to the following chart:
Also, in the pictures below, some problems and challenges around the country that highlighted the need to soil improvement are shown. These pictures are belonging to projects of ASACO before soil improvement actions.
The statistics and images clearly show that in encountering with problematic soils such as loose soils with low bearing capacity, high compressibility, liquefaction capability, …. New methods of soil improvement should be used to minimize the problems and damages.
Experts of ASACO have readiness to providing consultation, design and construction services, in soil improvement, structure improvement and seismic retrofitting to reduce these problems and damages around the country.
Soil improvement advantages
ASACO, by performing successful “projects” in national level has proved that construction of any civil project which is relevant to improvement of soil and structure and settlement control will be possible with lowest challenge.
With continues monitoring, performing control tests and quality evaluation in soil improvement methods, all purposes and advantages of these methods are as follows:
Improve the resistance properties of soil
Reduce amount of settlement and settlement control
increase bearing capacity
improve the permeability of soil
reduce the cost and time of construction
consider some specific conditions of industrial projects
reduce the environmental damages
Soil improvement methods
Depending on soil improvement purpose and considering region conditions, soil type, environmental factors, economic issues and allowable time for completion of the project, the suitable method for soil improvement is selected. Improvementof loose soils usingmicropile, jet grouting orhigh-pressure grouting, deep soil mixing,nailingand anchorage andstone columnhave been the most practical methods in this field. Different methods of soil improvement are shown in the pictures below.