Unconsolidated limestone

Equation 4-207 is used in carbonates (limestone and dolomite) and Equation 4-208 is used in unconsolidated to medium consolidated sandstones. A third Equation 4-209 can be used in highly consolidated sandstones. This is... 

Reg soils are closely associated with desertic regions. They have developed on stable surfaces where coarse, gravelly desert alluvium is exposed, and are characterized by a well-developed desert pavement and exhibit some well-defined soil horizons. They occur mostly on depositional surfaces where stones and gravels have been deposited since Neogene times. The surfaces commonly consist of stony, unconsolidated sedimentary deposits in which limestone, dolomite, chalk, flint and marl predominate, together with some fines (silt and clay). Sandstone and granite debris have also been reported to contribute to Reg formation. Less frequently, they form on sedimentary bedrock (Fig. 1.5). 

Sedimentary rocks underlying the study site range in age from Upper Cretaceous to late Eocene. A thin surficial deposit of unconsolidated, post-Eocene residuum overlies the bedrock. The geologic units pertinent to the study are, in ascending order, the Lisbon Formation, the Clinchfield Sand, the Ocala Limestone, and the undifferentiated residuum (Figure 3). 

The sand grades upward into an 11-foot-thick zone of fossiliferous, sandy limestone interbedded with thin lenses of unconsolidated quartz sand. This part of the sequence was deposited in a shallow marine environment (19). 

Beach sand, packed or fixed beds, soil, and gravel are unconsolidated porous media. Cloth, most naturally occurring rocks such as sandstone and limestone, concrete, bricks, paper, and wood are consolidated porous media. 

Precipitation is the main factor of water filling in Tianxin Coal Mine (opencast coal mine). The mining elevation of other coal mines is about 200 m while the depth is less than 300 m in general. After mining, the fissures would extend to the limestone in Neogene, unconsolidated layers in Quaternary... 

Porous media can be classified as unconsolidated and consolidated materials. Soils, clays, and packings of various sorts belong to the first class, while rocks such as sandstones and limestones belong to the second. Both classes are investigated in this section. The first two subsections are devoted to ordered or random systems of particles, and the third to a different model of consolidated rocks, based on the classical reconstruction technique [26,34]. Finally, a formula valid in the thick double layer limit is used to gather all the numerical results and also some experimental results found in the literature. 

Most collapses forming sinkholes result from roof failures of cavities in unconsolidated deposits above karstic limestone (Waltham and Fookes, 2003). These cavities are created when the unconsolidated deposits move or are eroded downwards into openings in the top of bedrock. The stability of residual soils that overlie cavernous limestone is a concern during the location and construction of buildings (Drumm and Yang, 2005). Collapse of bedrock roofs, as compared with the migration of unconsolidated deposits into openings in the top of bedrock, is rare. 

The youngest recent and sub-recent limestones include coral limestones, which occupy in some cases an intermediate position between (consolidated) rock and unconsolidated material. Deposits of shells, which can also be used in the manufacture of cement clinker, belong to the last-mentioned category. 

Aquifers vary enormously with respect to the volume of water they can hold and the speed with which water can flow through them. The volume of water in an aquifer depends on its porosity. In the case of unconsolidated aquifers, porosity is determined by the number and size of pores within and between soil particles. In bedrock aquifers, water is held, not in pores, but in fractures or holes in the rock. Spaces holding water in bedrock are referred to as secondary porosity, and the kinds of spaces depend on the geologic features of the bedrock. For example, a hard, crystaUine bedrock may hold water in cracks and fractures, whereas a soft bedrock such as karst limestone may have undergone erosion by groundwater over millions of years, resulting in a Swiss cheese network of large fissures and holes in which water is held. 

Many data exist on measured permeability and hydraulic conductivity of both consolidated and unconsolidated porous material. These data represent the geological material consisting of sand, silt, and clay particles that form the sediment bed plus the sandstone, limestone, and other aquifer material along the flow pathways. Selected data from various sources that represent bank and stream-bed materials appear in Table 11.1. A study of these data indicates that the range of values for any particular... 

Unconsolidated sediments Low consolidated sediments Consolidated sediments Eruptive rocks A Metamorphic rocks + From deep reflection seismic 0 Limestone 0 Sand, unconsolidated 1 1 — — -... 

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