Retaining wall is a relatively stiff wall that is used to support the soil mass laterally so that the soil can be maintained at different levels on both sides. The retaining wall is a structure designed to hold the ground to a slope that will not be naturally maintained (usually a steep slope, near vertical or vertical). They are used to tie the soil between two different elevations often in areas of terrain that have undesirable slopes or in areas where landscapes need to be heavily shaped and engineered for more specific purposes such as farming on hillsides or overpasses.
Video Retaining wall
Definisi
The retaining wall is a structure designed and constructed to withstand the lateral pressure of the ground, when there is a change in the desired height of the earth exceeding the ground angle of rest.
The basement wall is one of the retaining walls. But this term usually refers to the supporting support wall, which is a free standing structure with no lateral support on it. It is a cantilever from the foothold and rises above the class on one side to maintain a higher level on the opposite side. The walls must withstand lateral pressures generated by loose soil or, in some cases, water pressure.
Each supporting wall supports the ground's "wedge". Wedge is defined as ground that extends beyond the field of failure of the type of soil present on the wall site, and can be calculated after the friction angle of the soil is known. As the wall decline increases, the size of the sliding wedge decreases. This reduction lowers the pressure on the retaining wall.
The most important consideration in the proper design and installation of retaining walls is to recognize and counteract the propensity of retained material to move down the slope due to gravity. This creates lateral ground pressure behind the wall that depends on the angle of internal friction (phi) and cohesive strength (c) of the retained material, as well as the direction and magnitude of the retaining structural movement experienced.
The lateral zero soil pressure at the top of the wall and - in a homogeneous soil - increases proportionally to the maximum value at the lowest depth. Earth pressure will push the wall forward or cancel it if it is not handled properly. Also, any ground water behind a wall that is not dissipated by the drainage system causes hydrostatic pressure on the wall. Total pressure or thrust can be assumed to act on one third of the lowest depth to extend from a uniform height.
Unless the wall is designed to hold water, it is important to have proper drainage behind the wall to limit the pressure on the wall design value. The drainage material will reduce or eliminate hydrostatic pressure and improve the stability of the material behind the wall. Dry stone retaining walls are usually self-draining.
For example, the International Building Code requires that retaining walls are designed to ensure stability to the somersault, shear, excessive foundation stress and water enhancement; and that they are designed for a security factor of 1.5 against lateral shear and overturning.
Maps Retaining wall
Retaining wall type
Gravity
The gravity wall is dependent on its mass (rock, concrete or other heavy material) to withstand the pressure from the rear and may have a 'dough' setback to improve stability by leaning onto retained ground. For short landscape walls, they are often made of mortar or segmental concrete units (brick units). The dry-stacked gravity wall is somewhat flexible and does not require a rigid footing.
Earlier in the 20th century, higher retaining walls were often gravitational walls made of concrete or large rocks. Today, higher retaining walls are increasingly being built as composite gravity walls such as geosynthetics such as cellular cellular geocell retention or with precast facing; bronjong (stacked steel wire basket filled with stones); crib walls (cells construct cabin-style logs from precast or wooden concrete and filled with granular material); or walls nailed with soil (ground reinforced with steel rods and concrete).
Cantilevered
The supporting support wall is made of internal rods of steel reinforced concrete, poured concrete in place or castrated stone (often in reversed T shape). These walls contain cantilevers (like blocks) to a large structural footing, altering the horizontal pressure from the back of the wall to a vertical pressure in the ground below. Sometimes cantilevered walls are supported on the front, or include counterfort at the rear, to increase their strength to withstand high loads. Buttresses are short wing walls at right angles to the main wall trends. These walls require a rigid concrete foundation under the depth of seasonal ice. This type of wall uses much less material than traditional gravity walls.
Sheet Stacking
The stacking wall of the pile is usually used in soft soil and narrow space. The walls of piles of sheets are made of steel, vinyl or wooden planks pushed to the ground. For quick estimates the material is usually pushed 1/3 above the ground, 2/3 underground, but this can be changed depending on the environment. Higher pile wall walls will require tie-back anchors, or "dead man" placed on the ground at a distance behind the face of the wall, tied to a wall, usually with a cable or rod. Anchors are then placed behind a potential failed plane in the ground.
Bored pile
The tedious retaining wall of the pile is built by assembling a series of boring piles, followed by digging up excess soil. Depending on the project, a dull pile retaining wall may include a series of earth anchors, reinforcing beams, ground improvement operations and a shotcrete amplifier layer. This construction technique tends to be used in scenarios where the pile sheet is a valid construction solution, but where the level of vibration or noise generated by the stack driver is unacceptable.
Anchored
The anchored retaining wall can be constructed in one of the above mentioned styles but also includes the additional power of using a cable or other fixed anchored in the rock or dirt behind it. Usually pushed into the material by tedious, the anchor is then expanded at the end of the cable, either by mechanical means or often by injecting pressurized concrete, which expands to form a bulb in the ground. Technically complex, this method is very useful where high load is expected, or where the wall itself should be lean and otherwise would be too weak.
Technique to maintain alternatives
Nailing the ground
The ground nail is a technique in which sloping ground, excavation or retaining wall is reinforced by the insertion of relatively lean elements - usually reinforcing steel. The stems are usually fitted into the already drilled holes and then put in place or drilled and stirred simultaneously. They are usually installed without load on a slight downward trend. Seemed rigid or flexible (often sprayed concrete) or insulated ground nails can be used on the surface.
Soil-strengthened
A number of systems exist that not only consist of walls, but reduce the pressure of the soil working directly on the wall. It's usually used in combination with one of the other types of walls, although some may only use it as facing, ie. , for visual purposes.
Gabion Gabion
Strengthening of this type of soil, often also used without outer walls, consists of a "box" of wire, which is filled with rough cut stones or other materials. The mesh cage reduces some internal movement and strength, and also reduces the erosive style. The gabion walls are free retaining structures and are thus often built in locations where ground water is present. However, the management and control of groundwater in and around all retaining walls is important.
Mechanical Stabilization
The stable earth mechanic, also called MSE, is ground built with artificial strengthening through a layered horizontal mat (geosynthetics) fixed at the edges. This mat provides additional internal shear resistance beyond the simple gravity wall structure. Other options include steel ropes, also plated. Reinforcement of this type of soil usually requires an outward-facing wall (S.R.W.'s - Segmental Retaining Walls) to affix the coating to and vice versa.
The face of the wall is often from precast concrete units that can tolerate multiple differential motions. The reinforced ground mass, along with facing, then acts as an improved gravity wall. The reinforced mass must be built large enough to withstand the pressure from the ground behind it. Gravitational walls typically have to be at least 50 to 60 percent as deep or as thick as the height of a wall, and may have to be larger if there is a slope or additional cost on the wall.
Cell cage systems (geocells) are also used for sharp earth stabilization in gravity and retaining walls reinforced with geogrid. Geocell retaining walls are structurally stable under heavy loads and external loads, while structural flexibility offers very high seismic resistance. The outer fascia cells of the wall can be planted with vegetation to create a green wall.
See also
References
Further reading
- Bowles, J., (1968). Analysis and Design of the Foundation, McGraw-Hill Bookstore, New York
- Ching, F. D., Faia., R., S., & amp; Winkel, P. (2006). Building Codes are illustrated: Guidelines for Understanding International 2006
- Crosbie, M. & amp; Watson, D. (Eds.). (2005). Standard Time Saver for Architectural Design. New York, NY: McGraw-Hill.
Source of the article : Wikipedia
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