campaign Abstract: The soft ground remedy top quality, the quality of the whole project. Scientific and rational remedy of soft ground, soft ground can minimize and eliminate adverse effects on the upper component of the constructing.
I combined with concrete examples of the operate, focusing on the soft ground remedy of a number of methods and replacement cushion technique in sensible engineering foundation design and style.
Important words: soft ground handling characteristics of replacement cushion
1, Overview. Soft ground is a bad foundation, since the soft soil has low strength, high compressibility and permeability characteristics and weak, so soft on the construction of buildings, have to spend consideration to the deformation of foundation and stability. Soft foundation bearing capacity and deformation usually take place can not meet the design specifications of the problem, so measures are required to manage it. Ground therapy was made to increase the bearing capacity, to make certain the stability of the foundation to decrease the compressibility of soft soil, eventually reducing the basis of the settlement and differential settlement, to control the limit permitted in the design.
two, soft foundation remedy works and primary
2.1 features of soft ground. Soft soil, like mud, silty soil, red fill, mixed fill and loose saturated fine sand and silt, this type of soil as a foundation, the security of the project is detrimental to the performance of the engineering properties of the natural high water content material, porosity ratio, high compressibility, permeability, low shear strength. How to guarantee that buildings built on weak foundations, the stability, has always been a quite crucial Technology Topic.
two.2 soft ground treatment strategy. Currently, the primary approaches of soft ground therapy are: for cushion technique drainage consolidation compaction approach deep mixing grouting dynamic compaction.
three, replacement cushion for style applications
Basis throughout the design and style of buildings, frequently encountered soft ground remedy of the query, “replacement cushion strategy” is used broadly in approach, the following combination of practical engineering expertise to analyze and clarify.
“Developing foundations technical specifications” (JGJ79-2002) offers: replacement strategy suitable for mud, silty soil, loess, Earth Fill, Fill foundation and underground drain, dark ponds, shallow layer processing. Though the cushion of diverse materials, the stress distribution is slightly distinct, but test results of its carrying capacity is very close by subsidence observation information showed that the qualities of distinct materials related cushion, it can be of different components cushion created cushion of sand are equivalent calculation by the calculation. But on loess, soil, seasonal frozen soil and other particular processing by soil replacement, its primary objective is to eradicate handling wet soil subsidence, swelling and frost heaving, so to be regarded in the design should be the crucial to solving the difficulty is diverse. Replacement cushion cushion style including the determination to be the minimum width and thickness.
Had a 4-story brick workplace constructing, strip foundation below load-bearing walls, width 1.three m, depth 1.1 m, the upper base of the load acting on the developing for the 120KN / m, based on average weight degree 20KN/m3. For the silty clay soil surface, thick 1m, serious as 17.5KN/m3 second silty clay layer is thick, 15m, severe as 17.8KN/m3, water content w = 65% foundation bearing capacity worth of 45kPa third layer dense sand and gravel. Groundwater Jude Biao as 1m, since the soil is weak, can not afford the creating load, by comparison of several applications, can be decided directly by artificial replacement cushion method of construction, the constructing foundation therapy. In the cushion material, use of sand as bedding, its design and style value of bearing capacity calculated by f = 180KN/m2 (construction of the sand cushion density control in the secret level), serious take = 19.5KN/m3.
3.1 Calculation of the thickness of sand cushion.