Hydraulic and earth engineering – Drainage or irrigation
Reexamination Certificate
2000-02-10
2003-01-14
Lee, Jong-Suk (James) (Department: 3673)
Hydraulic and earth engineering
Drainage or irrigation
C405S043000, C405S046000, C405S302700, C404S002000
Reexamination Certificate
active
06505996
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to void-maintaining geosynthetic systems for the drainage of water and other fluids, and more particularly to geosynthetic structures having a void-maintaining core that may be sandwiched between attached or uni-formed geotextile layers. Geosynthetic structures of the invention are ideal for providing subsurface drainage for roadways and other large structures such as parking lots, retaining walls and buildings.
BACKGROUND OF THE INVENTION
The building of large structures such as roadways, buildings, parking lots, retaining walls, embankments and the like often involves the excavation, re-contouring and other movement of large quantities of earthen materials such as soil, rock, earth, gravel, sand and the like. Most large structures have underlying foundations of some sort to support the weight of the structure and thereby stabilize the structure in its desired position with respect to the earth and with respect to other parts of the same structure. For example, roadways and parking lots usually have foundations comprising a base aggregate immediately under the paved surface, and a subgrade layer under the base aggregate which supports the weight of both of the overlying structures. Commonly, both the base and subgrade are formed of stones, soil and other earthen materials and subjected repeatedly to grading, tamping or other compaction operations and thereby formed into a foundation of desired density, elevation, inclination and direction. Buildings commonly have concrete foundations or concrete slabs that support the weight of the overlying structure.
The presence of water or other fluids near, within or under such foundations can be quite disadvantageous. For example, water or other fluids in the foundation materials underlying such structures can cause hydraulic pore pressure buildup and reduction in the effective stress in the soil materials. These conditions can directly or indirectly contribute to failure of the underlying materials that support the overlying foundation and can thereby also cause a failure of the overlying structure. It is thus important to positively control the water or other fluids and dissipate pore pressure underlying large structures and in the vicinity of and underlying the foundations of such large structures.
The movement of soil particles around and underlying structures is not limited to that caused by the presence of fluids. Movement can occur from repeated or repetitive dynamic loads, as well as static loads that cause destabilizing stresses within the soil structure. One way of controlling such movement is to provide reinforcing products such as frameworks which are integral to the materials underlying the foundation, or within it, to thereby prevent or impede such undesired movement. Geosynthetics are materials often used to provide such a framework. The use of geosynthetics contributes to controlling movement of soil particles and structural fill materials in four primary ways:
1) By creating higher degrees of friction between the natural materials and the surface of the geosynthetic when compared to the frictional characteristics of the soil itself in order to minimize soil movement in horizontal, vertical and diagonal directions.
2) By confining soil fill material within the geosynthetic structure in an attempt to control lateral movement of soil particles.
3) By providing a nonporous, impermeable membrane type barrier that minimizes vertical migration of soil particles and fluids. At times, horizontal and diagonal movement of soil particles is impeded by roughening or texturing the geosynthetic in order to increase the friction between the soil and the geosynthetic.
4) By providing a semiporous, porous, or permeable barrier that minimizes vertical migration of soil particles by not allowing soil particles to move through openings in the geosynthetic that are effectively smaller than the diameter of the soil particles themselves, while also allowing fluids to migrate vertically, diagonally and horizontally irrespective of gravity through one or more layers of a single or multi-ply geosynthetic.
These porous, semiporporous or permeable geosynthetics allow fluids to pass vertically and horizontally through their structures. Capillary connections sometimes occur and are one aspect that allow fluids to migrate vertically and diagonally irrespective of gravity through multi-ply geosynthetics. Capillary connections are created by the contacting of two or more plys of geosynthetics and provide continuous vertical or diagonal capillary paths through which fluids may travel. Typically, capillary connections may appear in a semi-continuous pattern across the horizontal plane of a geosynthetic comprising more than one ply. These connections, which are formed when the polymer strands of one ply of a geosynthetic contact the polymer strands of another ply often occur when layers of geosynthetics are arranged or constructed to allow one ply to be placed directly on top of another ply. Polymer strands of individual geosynthetic plys assist fluid migration in the horizontal plane of the specific geosynthetic ply. This horizontal transmission of fluid can be expressed as a rate of flow per unit width within the plane of a geosynthetic and is typically called “transmissivity.” On the other hand, the vertical transmission rate of fluid, or “permittivity” of a geosynthetic is typically expressed by measuring the rate of flow per unit area per unit thickness. Permitivity is a quantifiable property that can be controlled during the maufacturering process.
Vertical and diagonal capillary connections can be created even when two or more plys of geosynthetic are arranged in substantially but parallel planes when polymer strands of one ply become in contact with the polymer strands of another ply. This can occur under the normal pressures that are placed upon the geosynthetic from the overlying soil burden which forces polymeric strands of the separate plys together thereby allowing fluids to migrate against gravity at the sites of the continuous capillary connections. The flow of fluids through a geosynthetic against gravity is often referred to as “wicking,” and is distinguished from permitivity. Wicking occurs after field installation of the product and is not a predictably quantifiable characteristic of the system but is dependent on a number of different factors. Wicking, the fluid transmission against gravity resulting from capillary connections created by the deformation and intercontact of geosynethic plys, is a property that is sometimes advantageous and other times disadvantageous.For example, in applications where the user desires water to be transmitted against gravity these, capillary connections may provide a benefit. In contrast, using geosynthetics in applications where the user does not want fluid to pass via the mechanism provided by the capillary connection can be a detriment to the particular structure.
In general, geosynthetics are manufactured as substantially planar, or sheetlike, products from polymeric materials. Geosynthetics are usually made in large scale, for example, several meters in width and many meters in length so that they are easily adaptable to large scale construction and landscaping uses. Some geosynthetics are flexible or fabric-like and therefore conform easily to uneven or rolling surfaces. Some geosynthetics are manufactured to be less flexible but to possess great tensile strength and resistance to stretching or great resistance to compression. Certain types of geosynthetic materials are used to reinforce large man-made structures, particularly those made of earthen materials such as gravel, sand and soil. In such uses, one purpose of using the geosynthetic is that of holding the earthen components together by providing a latticework or meshwork whose elements have a high resistence to stretching. By positioning the geosynthetic integral to the gravel, sand and soil, that is, with the gravel, sand and soil within the interstices of the geosynthetic, unwa
Capra Giovanni
Ianniello Peter J.
Zhao Aigen
Lee Jong-Suk (James)
Shaffer Gary L.
Tenax Corporation
LandOfFree
Drainage system with unitary void-maintaining geosynthetic... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drainage system with unitary void-maintaining geosynthetic..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drainage system with unitary void-maintaining geosynthetic... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3062821