Classification of weak soil in construction works

Weak soil is a type of soil that is not resistant to high impact. Both qualitative and quantitative, there are issues to be aware of. For example, in quantitative terms, it has low capacity, easily deformed, damaging structural works. Qualitatively, it is the type of soil that can not absorb the load of the above works. These concepts have been validated and recognized by science. Based on this, one compares the weight of the soil with 1.7 t / m3, if less than or equal to weak soil, which is the common soil in the following foundation treatment.

Types of common ground construction

Embankment

This soil is made up of human activity. Properties are uneven and fragmented. Structures can be divided into four categories:

- Waste in and out of mines.
- Soil, embankment (to create yards).
- Waste of mixed production land and daily life waste.
- Land includes mixed waste of industrial production and construction.

Basalt soil

This is a weak soil type with high porosity, dry density, high permeability, easy to sink.

Mud

Mud is a modern sediment formed primarily by the accumulation of fine, chemical or mechanical dispersions in the seabed, at the bottom of the lake, in the mud, etc. Mud only relates to water, new deposits, filled with water and weak with force.

The first stage of clay production is mud. They are formed in water with the presence of microorganisms. The mud always exceeds the flow limit and the pore coefficient e> 1 for clay sand and e> 1.5 for clay.

The composition of the mud is fine particles (<200 m), mud is likely to be sand clay, sandy clay, clay and sand, however only small sand. The strength of the sludge is very small, so the problem of cutting force (SCC) to friction force and adhesion force will not be very reasonable. The friction angle may be zero. SCC of sludge depends on deformation development speed. Only when the mud is dehydrated can the friction angle be calculated.

Construction problems of mud structures can only be made after the foundation treatment has taken place.

Slippery sand (weak sand)

Sand is born in the lagoon or the sea. Quartz is a major component of sand, minerals, sometimes containing impurities. Sand consists of small particles about 0.05 - 2mm.

Composed of fine sand, can be compacted or diluted significantly, discrete granular structure. This type of soil is called sand flow when it changes into a flow state, bearing dynamic load.

The most noticeable feature of the sand is its rapid compression, which is highly absorbent. When the sand consists of small particles, filled with saturated and organic water, the phenomenon of flowing sand sometimes makes the work and the building dangerous. Caution for weak sand two dangerous phenomena: flowing sand and thinning.

Sand is considered weak when the particle size is small, smooth and easy to slide down, while at the same time there is a discrete structure if it is saturated, containing many organic substances, lightning, which can be compressed and flowed significantly. These sand types, called sand streams, undergo vibration or shock, becoming liquid.

Clay weak

The composition of clay or clay relatively relative in the saturated water state, the intensity is not high. Need to treat the foundation. Clay consists of two components:

- The good dispersion (called clay minerals) consists of glue (0, 1 - 0.001mm) and very small particles (2 - 0.1mm). These minerals determine the mechanical properties of clay. The most common clay minerals are the three typical groups: marmotylite, kaolinite and ilit.