What Is Soil Mechanics?

Soil mechanics is a discipline that mainly studies the application of mechanics and hydraulics to earthworks. The development of soil mechanics can be traced back to the second half of the 18th century.

Soil mechanics

1773 French physicist

Important engineering properties of soil include:

In order to obtain engineering-related soil data, soil surveys must be performed, including field studies and laboratory tests. Reliable underground rock formation data must be obtained by drilling.

Soil mechanical foundation

The foundation is used to disperse the loads generated by itself, the superstructure and other forces in order to avoid excessive stress on the soil, which causes uneven settlement and cracking of the building. There are two types of foundation buildings: extended foundation and deep foundation. The extended foundation has loose feet (the feet are mainly used to support various pillars or load-bearing walls), and the raft foundation (usually composed of thick reinforced concrete slabs, which is located under the entire building or the main part, can widely disperse the load) Floating foundation (floating foundation is a box-shaped structure, that is, the earth is dug to a certain depth so that the earthwork weight is equal to the total weight of the building, so that the contact pressure of the building is roughly equal to the original soil pressure). There are two types of deep foundations: pile foundations (the piles are driven into the ground, and the pile foundations are divided into bearing piles and friction piles) and caissons piles (larger than pile foundations, which need to be excavated in situ to form a mold and are generally poured with concrete).

Soil mechanics slope

Engineering slopes include road or railway ballasts, river dams, open pit mines, trenches, industrial and mining waste dumps, flood banks, earthen dams, and road, rail, and airport fills. Under the influence of gravity and friction, cohesion and other restraining forces, the topsoil particles maintain a static balance. Landslides occur when this static balance is disrupted for various reasons. The safety factor of the slope (the ratio of the binding force to the inducement force) is generally 1.5 to 2.0. To improve the stability of the slope, the drainage condition must be improved first, and water should be prevented from entering the soil layer. In addition, trees can be planted and the slope can be leveled. surface. This method of slope stabilization is also applicable to various dykes. Pay attention to the waterproof performance of reservoirs or diversion dams. Leakage can affect the structural stability of the dams. The core of the dam uses water-impermeable materials to reduce water seepage; the slope is permeable, but it should prevent water erosion; the transition area between the dam core and the slope is of medium-granularity material to prevent the center fine material from laterally seeping with water seepage Missing.

Soil mechanics pavement

Roads, highways, airport runways and taxiways all need to be paved, usually on natural soil or on fill. According to its load dispersion method, the pavement is divided into rigid and flexible. The former has high flexural strength, which can disperse concentrated loads on a large support surface. Generally, it is constructed directly on the roadbed or sand and stone base with cement concrete. Flexible pavement has weak flexural strength, but it must be designed with sufficient thickness and low subgrade stress. This pavement consists of a base layer of granular material and a wear-resistant layer of gravel asphalt structure. The underground tunnel excavation methods are divided into hard rock excavation method, soft soil excavation method, immersed pipe method and digging and filling method. Most of the hard rock excavation uses drilling blasting technology, and there are also tunnel boring machines. Tunneling machines are often used for soft soil excavation. If the tunnel is to pass through hard soil, the lining board method can be used; compressed air technology can be used during construction, but this is only applicable to tunnels with smaller diameters. In addition, shield tunneling can be used. The immersed pipe method is most suitable for drilling underwater tunnels. The tunnel shell is pre-built with reinforced reinforced concrete, then transported to a predetermined water surface and connected after sinking. The dig-and-fill method is often used in tunnel engineering, especially for shallow tunnels.