Patent Application
20150033842
The disclosure relates in general to testing devices. More particularly, the present disclosure relates to a device for estimating the scour-depth potential of soils relied upon to support structural foundations located in flowing water. Most precisely, the present disclosure is directed to a field testing device for measuring the scour-depth potential of soils in-situ utilizing a confined flow of water having a defined shear stress and symmetrical pressure distribution across the soil surface test site.
An in-situ scour testing device for more accurately determining the scour-depth potential of soils relied upon to support structural foundations placed in flowing water is disclosed. The device measures the scour potential in-situ, in relative terms, to the scour potential of fine sand using a columnar containment vessel driven into the soil to be tested at a rate commensurate to the erosion experienced during testing.
The containment vessel has an open end which is driven into the soil to isolate a core sample of soil within the containment vessel to be tested. A closed loop water system, including a variable-speed pump and a filtration system for removing scour debris from the water within the closed loop system, provides a controlled representative water flow across the surface of the core sample within the containment vessel to simulate the horizontal flow of the free flowing water outside the containment vessel.
Within the columnar containment vessel is a cutting head as an aid in directing the representative water flow in a generally horizontal direction across the surface of the soil to be tested. Additionally, the cutting head serves to aid in the evacuation of eroded soil from with the containment vessel through an included exhaust port. The exhaust port is part of the closed loop water system. The exhausted scour debris is removed from the closed loop system by use of a filtration medium prior to re-introducing the water into the portion of the closed loop water system that returns water to the containment vessel to be used again.
Various measurements relating to the scour potential of the in-situ soil can be determined from use of the presently disclosed device, including the minimum safe depth for the placement of required foundation supports, the rate of scour in relation to the speed of the water flow, the scour potential for the various soil types occurring at various depths in relation to a defined scour rate for fine sand, and others.
Additional advantages of the disclosure are set forth in, or will be apparent to those of ordinary skill in the art from, the detailed description as follows. It should also be appreciated that modifications and variations to the specifically illustrated and discussed features and materials hereof may be practiced in various embodiments and uses of this disclosure without departing from the spirit and scope thereof. Such variations may include, but are not limited to, substitutions of equivalent means, features, and materials for those shown or discussed, and the functional or positional reversal of various parts, features or the like.
Still further, it is to be understood that different embodiments of this disclosure may include various combinations or configurations of presently disclosed features, elements, or their equivalents (including combinations of features or configurations not expressly shown in the figures or stated in the detailed description).
These and other features, aspects and advantages of the present disclosure will become better understood with reference to the following descriptions and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate at least one embodiment and, together with the descriptions, serve to explain the principles of the disclosure.
A full and enabling disclosure, directed to one of ordinary skill in the art, is set forth in this specification, which makes reference to the appended figures, in which:
Repeated use of reference characters throughout the present specification and appended drawings is intended to represent the same or analogous features or elements of the present disclosure.
Reference will now be made in detail to the presently preferred embodiment or embodiments of the disclosure, examples of which are fully represented in the accompanying drawings. Such examples are provided by way of an explanation of the disclosure, not a limitation thereof. It should be apparent to those of ordinary skill in the art that various modifications and variations can be made to the presently disclosed embodiments without departing from the spirit and scope thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a further embodiment. Still further, variations in selection of materials and/or characteristics may be practiced, to satisfy particular desired user criteria. Thus, it is intended that the present disclosure cover such modifications and variations as coming within the scope of the present features and their equivalents.
As disclosed above the present invention is particularly concerned with measuring, relative to fine sand, the scour-depth potential of soils relied upon to support structure foundations placed in flowing water.
Associated with the capped end (9) of the containment vessel (2) is a closed loop water system (4, 5, 6, 7, 8 and 13) for pumping water into and out of the containment vessel (2) to simulate the scour potential of flowing water across the soil (11) surface enclosed within the open end (10) of the containment vessel (2). The closed loop water system (4, 5, 6, 7, 8 and 13) begins with water reservoir (8) which retains an amount of water sufficient to fill the containment vessel (2) and the remainder of the closed loop system (4, 5, 6, 7 and 8). A variable-speed pump (5) draws water out of the reservoir (8) and pushes it through circulation piping (4) into the containment vessel (2) near the capped end (9). It is preferred that the water be introduced at multiple locations near the capped end (9) of the containment vessel (2) to prevent any artificial scour due to the introduction of the water at only a single point about the inner perimeter of the vessel (2).
As best seen in
In operation, the open end (10) of the containment vessel (2) is advanced into the soil (11) by an external driving device (3) controlled by a sensor (14) located above the cutting head (1), and various control computers (15). The rate of advance of the open end (10) of the containment vessel (2) is determined by the relative resistance of the soil (11) to the artificial erosion and the shear characteristics generated by the water flowing over the soil (11) surface beneath the cutting head (1). Mechanically, this is measured as a resistance to the free-pistoning cutting head (1) fully extending within the containment vessel. The sensor (14) comprises two parts. The first is located on an inner wall of the columnar containment vessel and the corresponding second part is located above the cutting head on the outside wall of a portion of circulation piping (4) associated with exhaust port (13). The shear characteristics of the flowing water may be artificially varied (i.e., lowered) with increasing depth into the soil (11) to better simulate the natural decay of the scouring mechanism with depth.
The variable-speed pump (5) pushes water into the containment vessel (2), through the annular space (12) between the inner wall of the vessel (2) and the outer diameter of the cutting head (1) and horizontally across the surface of the soil (11). Such flow of water creates scour debris. As part of the closed loop water system (4, 5, 6, 7, 8 and 13), the cutting head (1) includes a centrally located exit port (13) for exhausting water and scour debris from beneath the cutting head (1). Additional circulation piping (4) carries the exhaust water and scour debris through the exhaust port (13) to a filter (6). The filter (6) allows clean water to return to the water reservoir (8) for re-use while directing the scour debris to a collection and removal vessel (7).
The containment vessel (2) will cease advancing into the soil (11) when equilibrium between the shearing force of the flowing water and the erosion resistance of the in-situ soil (11) is reached. The depth reached by the cutting head bottom surface (16) can then be compared to the worst case scenario determined through traditional empirical equations to adjust the minimum required construction depth for structural foundations used to support constructions in-situ.
In the disclosed embodiment, it is preferred that the columnar containment vessel (2) is made of steel, however, it should be noted that any suitably resilient material sufficient to withstand the normal wear-and-tear to be expected on such a testing device would be acceptable for use in the present device. Similarly, while the containment vessel (2) is defined as generally columnar or tubular, any shape suitable to assure functionality of the device while retaining accuracy of the measurements taken would be suitable for the purposes of the present disclosure. Still further, while the shape of the cutting head's bottom surface (16) and the plurality of vanes (17) extending therefrom have been chosen to assure a symmetrical pressure distribution while allowing a controlled flow rate of the water to more accurately simulate the natural conditions of the site being tested, alternative shapes and numbers of vanes are contemplated by the present disclosure that would similarly assure such performance characteristics.
Although a detailed description of one embodiment of the present disclosure has been expressed using specific terms and devices, such description is for illustrative purposes only. The words used are words of description rather than of limitation. It is understood that changes and variations may be made by those of ordinary skill in the art without departing from the spirit or scope of the present disclosure, which is set forth in the following claims. Additionally, it should be understood that aspects of various other embodiments may be interchanged either in whole or in part. Therefore, the spirit and scope of the appended claims should not be limited to the detailed description contained herein.
