This disclosure relates generally to forms for constructing subsurface structural elements that redirect soil forces.
Foundations typically form the lowest part of an architectural structure and are generally either shallow or deep. Foundations are also sometimes called basework, for example, in the context of large structures. Foundations may be constructed using forms (or formwork). Forms are molds into which concrete (or another material) may be poured to shape the concrete to a desired shape.
Some embodiments may include a form for constructing at least a portion of a structural foundation. The form may include one or more wall forming portions configured to shape a foundation material (e.g., concrete) to form one or more respective walls of at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.) of the foundation. The form may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element extends from a surface-level base of the foundation to a subsurface level. Furthermore, the form may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation rather than have the soil forces crack or otherwise damage the foundation.
Some embodiments may include a foundation for supporting a structure. For instance, the foundation may include a base (e.g., a surface-level base) and at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.). The subsurface structural element(s) may extend from the base to a subsurface level. Furthermore, the subsurface structural element may be shaped such that it redirects soil forces to vertically displace the foundation. In some cases, the subsurface structural element(s) may include a triangular cross section and/or a trapezoidal cross section.
Some embodiments may include a method of constructing a foundation. The method may include forming at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.) that extends from a surface-level base of the foundation to a subsurface level. The subsurface structural element may be configured to redirect soil forces to vertically displace the foundation.
This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
“Comprising.” This term is open-ended. As used in the appended claims, this term does not foreclose additional structure or steps. Consider a claim that recites: “An apparatus comprising one or more processor units . . . ”. Such a claim does not foreclose the apparatus from including additional components (e.g., a network interface unit, graphics circuitry, etc.).
“Configured To.” Various units, circuits, or other components may be described or claimed as “configured to” perform a task or tasks. In such contexts, “configured to” is used to connote structure by indicating that the units/circuits/components include structure (e.g., circuitry) that performs those task or tasks during operation. As such, the unit/circuit/component can be said to be configured to perform the task even when the specified unit/circuit/component is not currently operational (e.g., is not on). The units/circuits/components used with the “configured to” language include hardware—for example, circuits, memory storing program instructions executable to implement the operation, etc. Reciting that a unit/circuit/component is “configured to” perform one or more tasks is expressly intended not to invoke 35 U.S.C. § 112, sixth paragraph, for that unit/circuit/component. Additionally, “configured to” can include generic structure (e.g., generic circuitry) that is manipulated by software and/or firmware (e.g., an FPGA or a general-purpose processor executing software) to operate in manner that is capable of performing the task(s) at issue. “Configure to” may also include adapting a manufacturing process (e.g., a semiconductor fabrication facility) to fabricate devices (e.g., integrated circuits) that are adapted to implement or perform one or more tasks.
“First,” “Second,” etc. As used herein, these terms are used as labels for nouns that they precede, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.). For example, a buffer circuit may be described herein as performing write operations for “first” and “second” values. The terms “first” and “second” do not necessarily imply that the first value must be written before the second value.
“Based On.” As used herein, this term is used to describe one or more factors that affect a determination. This term does not foreclose additional factors that may affect a determination. That is, a determination may be solely based on those factors or based, at least in part, on those factors. Consider the phrase “determine A based on B.” While in this case, B is a factor that affects the determination of A, such a phrase does not foreclose the determination of A from also being based on C. In other instances, A may be determined based solely on B.
Embodiments described herein relate to construction of subsurface structural elements that are configured to redirect soil forces. For instance, a form may be configured to form a subsurface structural element such that the subsurface structural element redirects soil forces to vertically displace a foundation rather than have the soil forces crack or otherwise damage the foundation. The soil forces may include force vectors generated while the soils expand against walls/surfaces of the subsurface structural element. In some embodiments, the soil forces generated by expansive soils while expanding against the sides of the subsurface structural element are less than 90 degrees to the surface of the subsurface structural element, thus creating both a horizontal force vector and a vertical force vector, with the vertical force vector causing the foundation to shift or move vertically.
Some embodiments include a form for constructing at least a portion of a structural foundation (also referred to herein as the “foundation”). As used herein, the term “foundation” may refer to any type of load bearing architectural structure, including but not limited to footings, concrete slabs, concrete slab-on-grade, impact driven piles, drilled shafts, caissons, helical piles, geo-piers, and earth stabilized columns.
The form may include one or more wall forming portions configured to shape a foundation material (e.g., concrete) to form one or more respective walls of at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.) of the foundation. The form may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element extends from a surface-level base of the foundation to a subsurface level. Furthermore, the form may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation.
In some embodiments, the wall forming portions may include a first wall forming portion and a second wall forming portion. The first wall forming portion may be configured to shape the foundation material to form a first surface (e.g., a planar surface, a concave surface, a convex surface, etc.) of a first wall of the subsurface structural element. The first surface may be formed, via the first wall forming portion, such that it includes a first top portion that meets the surface-level base at a first non-zero angle, and a first bottom portion that is opposite the first top portion. The second wall forming portion may be configured to shape the foundation material to form a second surface (e.g., a planar surface, a concave surface, a convex surface, etc.) of a second wall of the subsurface structural element. The second surface may be formed, via the second wall forming portion, such that it includes a second top portion that meets the surface-level base at the first non-zero angle (or a different angle), and a second bottom portion that is opposite the second top portion. In some examples, the second bottom portion may meet the first bottom portion at a second non-zero angle. The first non-zero angle and the second non-zero angle may be the same in some cases. However, in other cases, the first non-zero angle and the second non-zero angle may be different.
In some examples, the form may include one or more termination forming portions configured to shape the foundation material to form one or more respective termination portions of at least one subsurface structural element. The termination portions may be formed, via the termination forming portions, such that each of the termination portions is adjacent to a bottom portion of at least one of the respective walls.
According to some embodiments, the form may include a lining portion and/or a filling portion. The lining portion may include at least one lining that is adjacent to subsurface soil. The filling portion may include a filling material that at least partially fills a gap between at least one subsurface structural element and the lining portion or the subsurface soil. In some examples, the wall forming portions of the form may include at least part of the filling portion. For instance, the filling portion may define a form boundary that may function, at least in part, as the wall forming portions.
In some embodiments, the lining portion may include multiple linings. For example, the lining portion may include a first lining that is adjacent to the subsurface soil and a second lining. Furthermore, the lining portion may include a third lining and/or a friction reducing agent (e.g., a lubricant). The third lining may be located between the first lining and the second lining. For instance, the third lining may be configured to reduce friction between the first lining and the second lining. Likewise, the friction reducing agent may be disposed between the first lining and the second lining. For instance, the friction reducing agent may be configured to form a friction reducing layer between the first lining and the second lining.
In various embodiments, the form may be a soil form. For instance, soil may be excavated to define a cavity that may be used as a form to receive and shape the foundation material. Additionally, or alternatively, the form may be a removable form that may be removed from the foundation (e.g., after the foundation is constructed using the form) and/or a permanent form that is intended to permanently remain with the foundation.
Some embodiments may include a foundation for supporting a structure. For instance, the foundation may include a base (e.g., a surface-level base) and at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.). The subsurface structural element(s) may extend from the base to a subsurface level. Furthermore, the subsurface structural element may be shaped such that it redirects soil forces to vertically displace the foundation. In some cases, the subsurface structural element(s) may include a triangular cross section and/or a trapezoidal cross section.
In some examples, at least a portion of the base may extend along a horizontally oriented plane. Additionally, or alternatively, the subsurface structural element may be symmetrical about a vertically oriented plane.
In some embodiments, the subsurface structural element may include a first surface and a second surface, each of which may be planar, concave, convex, etc. The first surface may include a first top portion that meets the base at a first non-zero angle, and a first bottom portion that is opposite the first top portion. The second surface may include a second top portion that meets the base at the first non-zero angle (or a different angle), and a second bottom portion that is opposite the second top portion. In some examples, the second bottom portion may meet the first bottom portion at a second non-zero angle. The first non-zero angle and the second non-zero angle may be the same in some cases. However, in other cases, the first non-zero angle and the second non-zero angle may be different.
In some embodiments, the subsurface structural element may include a third surface (e.g., a planar surface, a concave surface, a convex surface, etc.) that extends from the first bottom portion to the second bottom portion. For instance, the third surface may be included in the subsurface structural element instead of the first bottom portion directly meeting with the second bottom portion. In some instances, the third surface may at least partially define a termination portion of the subsurface structural element.
In some examples, the subsurface structural element(s) may include a beam and/or a pile. For instance, the beam may have a longest dimension that extends substantially parallel to at least a portion of the base. The pile may have a longest dimension that extends substantially perpendicular to at least a portion of the base.
Some embodiments may include a method of constructing a foundation. The method may include forming at least one subsurface structural element (e.g., a subsurface beam, a subsurface pile, etc.) that extends from a surface-level base of the foundation to a subsurface level. The subsurface structural element may be configured to redirect soil forces to vertically displace the foundation.
In various embodiments, the method may include excavating a ground area to produce a cavity that is at least partially defined by subsurface soil. Furthermore, the method may include placing a form within the cavity, and pouring concrete within the form. The form may be configured to shape the concrete to form the subsurface structural element.
In some embodiments, the method may include constructing a form. For instance, construction of the form may include excavating a ground area to produce a cavity that is at least partially defined by surface soil, placing one or more linings within the cavity to form a lining layer, and/or filling a portion of the cavity with a filling material to form a filling layer. In some instances, one or more linings may be placed within the cavity such that at least one of the linings is adjacent to the subsurface soil.
In some implementations, the method may include calculating one or more Atterberg limits (e.g., a shrinkage limit, a plastic limit, and/or a liquid limit) corresponding to soil within the subsurface level. Furthermore, the method may include determining one or more design variables associated with the subsurface structural element based at least in part on the calculated Atterberg limit(s). In some cases, the subsurface structural element may be formed based at least in part on the determined design parameter(s).
In various embodiments, a form 114 may be used to construct at least a portion of the foundation 102. For instance, the form 114 may be used to construct the subsurface structural element 106. In some examples, the form 114 may be a soil form, a removable form, and/or a permanent form. In some embodiments, the form may be constructed of wood, metal, plastic, fiber glass, and/or resins, etc.
As will be discussed in further detail below with reference to
As illustrated in
In some embodiments, the lining portion 122 may include multiple linings. For example, the lining portion 122 may include a first lining that is adjacent to the subsurface soil 112 and a second lining. Furthermore, the lining portion 122 may include a third lining and/or a friction reducing agent (e.g., a lubricant). The third lining may be located between the first lining and the second lining. For instance, the third lining may be configured to reduce friction between the first lining and the second lining. Likewise, the friction reducing agent may be disposed between the first lining and the second lining. For instance, the friction reducing agent may be configured to form a friction reducing layer between the first lining and the second lining.
In some examples, at least a portion of the base 104 may extend along a horizontally oriented plane (e.g., a plane that is orthogonal to the page of
The design variables 200 may be adjusted based on the desired performance of the subsurface structural element 106 and/or the foundation 102 that is to be constructed. For instance, the design variables 200 may be adjusted to improve performance of the subsurface structural element 106 and/or the foundation 102 in expansive soils and clays. In various embodiments, the design variables 200 may include form type 202, wall shape 204, wall angle 206, termination shape 208, linings 210, and/or gap fillings 212.
In some embodiments, the form type 202 design variables may include a soil form 214, a removable form 216, and/or a permanent form 218. With a soil form 214, the soil 112 itself may be shaped such that the soil 112 serves as a form 114. For instance, soil may be excavated to define a cavity that may be used as a form to receive and shape the foundation material. A removable form 216 may be a form 114 configured to be removed from the subsurface structural element 106 and/or the foundation 102 after construction of the subsurface structural element 106 and/or the foundation 102. A permanent form 218 may be a form 114 that is configured to remain with the subsurface structural element 106 and/or the foundation 102 after construction of the subsurface structural element 106 and/or the foundation 102.
In some examples, the wall shape 204 design variables may include a straight wall 220, a convex wall 222, a concave wall 224, and/or a multi-segment wall 226. For instance, the form 114 may include one or more wall forming portions having straight walls 220. The straight walls 220 may be configured to shape a foundation material to form corresponding straight walls of the subsurface structural element 106. Additionally, or alternatively, the form 114 may include one or more wall forming portions having convex walls 222. The convex walls 222 may be configured to shape the foundation material to form corresponding convex walls of the subsurface structural element 106. Additionally, or alternatively, the form 114 may include one or more wall forming portions having concave walls 224. The concave walls 224 may be configured to shape the foundation material to form corresponding concave walls of the subsurface structural element 106.
In some embodiments, the form 114 may include one or more wall forming portions having multi-segment walls 226. The multi-segment walls 226 may include multiple segments of straight walls 220, convex walls 222, concave walls 224, or combinations thereof.
In various embodiments, the wall angle 206 design variables may include a greater than 90 degrees wall angle 228, a 90 degrees wall angle 230, and/or a less than 90 degrees wall angle 232. The wall angle 206 design variables may refer to the angle at which a wall forming portion of the form 114 meets the base 104 of the foundation 102 or a base forming portion of the form 114. Additionally, or alternatively, the wall angle 206 design variables may refer to the angle at which a wall of the resulting subsurface structural element 106 (i.e., the subsurface structural element 106 that is to be formed using the form 114) is to meet the base 104 of the foundation 102. In
In some embodiments, the termination shape 208 design variables may include a point termination shape 234, a straight termination shape 236, a convex termination shape 238, a concave termination shape 240, and/or a multi-segment termination shape 242. The termination shape 208 design variables may refer to a shape of a termination forming portion of the form 114. Additionally, or alternatively, the termination shape 208 design variables may refer to a shape of a termination portion of the resulting subsurface structural element 106 (i.e., the subsurface structural element 106 that is to be formed using the form 114). In some examples, the form 114 may include one or more termination forming portions configured to shape the foundation material to form one or more respective termination portions of the subsurface structural element. In some cases, each of the termination portions may be adjacent to a bottom portion of a wall of the subsurface structural element 106.
In
In various examples, the linings 210 design variables may include no linings 244, one lining 246, two linings 248, three linings 250, and/or more than three linings 252. As discussed above with reference to
According to another particular non-limiting example, the lining portion 122 may include three linings 250. For instance, a low friction middle lining 256 may be disposed between two other linings to ease movement between the two other linings. The low friction middle lining 256 may have a low coefficient of friction to reduce friction between the two other linings. In some cases, a middle friction reducing agent 254 may function as a low friction middle lining 256.
Additionally, or alternatively, a middle friction increasing agent and/or a high friction middle lining may be disposed between two linings to increase friction between the two linings.
In some embodiments, the gap fillings 212 design variables may include a friction fill 258, a moisture fill 260, and/or a compression fill 262. As discussed above with reference to
In some examples, the filling material may comprise a friction fill material 258. In some embodiments, the friction fill material 258 may be configured to increase friction 264 between the soil 112 and the subsurface structural element 106. In other embodiments, the friction fill material 258 may be configured to reduce friction between the soil 112 and the subsurface structural element 106.
Additionally, or alternatively, the filling material may comprise a moisture fill material 260. In some embodiments, the moisture fill material 260 may be configured to increase moisture 268 of the soil 112 around the subsurface structural element 106. In other embodiments, the moisture fill material 260 may be configured to reduce moisture 270 of the soil 112 around the subsurface structural element 106.
Additionally, or alternatively, the filling material may comprise a compression fill material 262. In some embodiments, the compression fill material 262 may be compressible 272 to absorb soil forces before they reach the subsurface structural element 106. In other embodiments, the compression fill material 262 may be incompressible 274, or substantially incompressible, such that the compression fill material 262 transmits soil forces directly to the subsurface structural element 106 with little or no loss of force.
It should be understood that the filling material may have one or more of the properties described above with reference to the friction fill material 258, moisture fill material 260, and the compression fill material 262. For instance, a filling material may both reduce friction 266 and be incompressible 274, such as smooth, round rocks.
In some embodiments, no filling material may be used to fill the gap between the subsurface structural element 106 and the lining portion 122 or the subsurface soil 112. That is, the gap may comprise an unfilled void or empty space between the soil 112 (or the lining portion 122) and the subsurface structural element 106.
In some examples, the form 300 may include one or more wall forming portions configured to shape the foundation material to form one or more respective walls of the subsurface structural element. The form 300 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element extends from the surface-level base of the foundation to a subsurface level. Furthermore, the form 300 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation.
In some embodiments, the wall forming portions may include a first wall forming portion 304 and a second wall forming portion 306. The first wall forming portion 304 may be configured to shape the foundation material to form a first surface of a first wall of the subsurface structural element. The first surface may be formed, via the first wall forming portion 304, such that it includes a first top portion that meets the surface-level base at a first non-zero angle, and a first bottom portion that is opposite the first top portion. The second wall forming portion 306 may be configured to shape the foundation material to form a second surface of a second wall of the subsurface structural element. The second surface may be formed, via the second wall forming portion, such that it includes a second top portion that meets the surface-level base at the first non-zero angle (or a different angle), and a second bottom portion that is opposite the second top portion. In some examples, the second bottom portion may meet the first bottom portion at a second non-zero angle. The first non-zero angle and the second non-zero angle may be the same in some cases. However, in other cases, the first non-zero angle and the second non-zero angle may be different.
In some examples, the form 300 may include a termination forming portion 308 configured to shape the foundation material to form a corresponding termination portion of the subsurface structural element. As illustrated in
In various embodiments, the form 300 may be used to construct a subsurface structural element that is V-shaped and/or a subsurface structural element that has a triangular cross-section. In some examples, the form 300 may be used to construct a subsurface beam.
In some embodiments, the subsurface structural element 400 may include a first surface 404 and a second surface 406. The first surface 404 may include a first top portion 408 that meets the base 402 at a first non-zero angle, and a first bottom portion 410 that is opposite the first top portion 408. For instance, as illustrated in
In various embodiments, the subsurface structural element 400 may be V-shaped and/or have a triangular cross-section such that it is capable of redirecting soil forces to vertically displace the foundation. In some examples, the subsurface structural element 400 may be a beam that has a longest dimension that extends substantially parallel to at least a portion of the base 402.
In some examples, the form 500 may include a wall forming portion 504 configured to shape the foundation material to form a conical wall of the subsurface structural element. The form 500 may be configured to shape, based at least in part on the wall forming portion 504, the subsurface structural element such that the subsurface structural element extends from the surface-level base of the foundation to a subsurface level. Furthermore, the form 500 may be configured to shape, based at least in part on the wall forming portion 504, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation.
In some examples, the form 500 may include a termination forming portion 506 configured to shape the foundation material to form a corresponding termination portion of the subsurface structural element. As illustrated in
In various embodiments, the form 500 may be used to construct a subsurface structural element that is conical and/or a subsurface structural element that has a triangular cross-section. In some examples, the form 500 may be used to construct a subsurface conical pile.
In some embodiments, the subsurface structural element 600 may include a conical surface 604. The surface may include a top portion that meets the base 602 at a non-zero angle, and a bottom portion that is opposite the top portion. For instance, as illustrated in
In various embodiments, the subsurface structural element 600 may be conical and/or have a triangular cross-section such that it is capable of redirecting soil forces to vertically displace the foundation. In some examples, the subsurface structural element 600 may be a pile that has a longest dimension that extends substantially perpendicular to at least a portion of the base 602.
In some examples, the form 700 may include one or more wall forming portions configured to shape the foundation material to form one or more respective walls of the subsurface structural element. The form 700 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element extends from the surface-level base of the foundation to a subsurface level. Furthermore, the form 700 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation.
In some embodiments, the wall forming portions may include a first wall forming portion 704, a second wall forming portion 706, and a third wall forming portion 706. The first wall forming portion 704 may be configured to shape the foundation material to form a first surface of a first wall of the subsurface structural element. The second wall forming portion 706 may be configured to shape the foundation material to form a second surface of a second wall of the subsurface structural element. The third wall forming portion 708 may be configured to shape the foundation material to form a third surface of a third wall of the subsurface structural element. As illustrated in
In various embodiments, the form 700 may be used to construct a subsurface structural element that is pyramidal and/or a subsurface structural element that has a triangular cross-section. In some examples, the form 700 may be used to construct a subsurface pyramidal pile.
In some embodiments, the subsurface structural element 800 may include a first surface 804, a second surface 806, and a third surface 808. The first surface 804 may include a first top portion that meets the base 802 at a non-zero angle, and a first bottom portion that is opposite the first top portion. For instance, as illustrated in
In various embodiments, the subsurface structural element 800 may be pyramidal and/or have a triangular cross-section such that it is capable of redirecting soil forces to vertically displace the foundation. In some examples, the subsurface structural element 800 may be a pile that has a longest dimension that extends substantially perpendicular to at least a portion of the base 802.
In some examples, the form 900 may include one or more wall forming portions configured to shape the foundation material to form one or more respective walls of the subsurface structural element. The form 900 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element extends from the surface-level base of the foundation to a subsurface level. Furthermore, the form 900 may be configured to shape, based at least in part on the wall forming portions, the subsurface structural element such that the subsurface structural element is configured to redirect soil forces to vertically displace the foundation.
In some embodiments, the wall forming portions may include a first wall forming portion 904 and a second wall forming portion 906. The first wall forming portion 904 may be configured to shape the foundation material to form a first surface of a first wall of the subsurface structural element. The second wall forming portion 906 may be configured to shape the foundation material to form a second surface of a second wall of the subsurface structural element. As illustrated in
In various embodiments, the form 900 may be used to construct a subsurface structural element that is tapered and/or a subsurface structural element that has a trapezoidal cross-section. In some examples, the form 900 may be used to construct a subsurface trapezoidal beam.
In some embodiments, the subsurface structural element 1000 may include a first surface 1004 and a second surface 1006. The first surface 1004 may include a first top portion that meets the base 1002 at a non-zero angle, and a first bottom portion that is opposite the first top portion. For instance, as illustrated in
In some embodiments, the subsurface structural element may include a third surface that extends from the first bottom portion to the second bottom portion. For instance, the third surface may at least partially define a termination portion 1008 of the subsurface structural element that has a straight termination shape.
In various embodiments, the subsurface structural element 1000 may be tapered and/or have a trapezoidal cross-section such that it is capable of redirecting soil forces to vertically displace the foundation. In some examples, the subsurface structural element 1000 may be a trapezoidal beam that has a longest dimension that extends substantially parallel to at least a portion of the base 1002. Furthermore, the subsurface structural element 1000 may include “locking taper” wall angles that are less than 90 degrees, which may cause expansive soils to grip the subsurface structural element 1000 tightly.
In
In
In
At 1304, the method 1300 may include determining one or more design variables associated with the subsurface structural element. In various embodiments, the design variables may include one or more of the design variables discussed above with reference to
In some examples, the design variables may be determined based at least in part on the calculated Atterberg limits. The Atterberg limits may include a shrinkage limit, a plastic limit, and/or a liquid limit.
The shrinkage limit (SL) may be the water content of a soil at which further loss of moisture will not result in any more volume reduction. In some embodiments, the shrinkage limit may be calculated using ASTM International D4943.
The plastic limit (PL) may be calculated using ASTM Standard D4318, which includes rolling out a thread of a fine portion of a soil on a flat, non-porous surface. The thread will retain its shape down to a narrow diameter if the moisture content of the soil is at a level where the soil behavior is plastic. The plastic limit may be the moisture content at which the thread breaks apart at a diameter of 3.2 mm. If the thread cannot be rolled out to a diameter of 3.2 mm, then the soil may be considered non-plastic.
The liquid limit (LL) may be the water content of a soil at which the behavior of a soil (e.g., a clayey soil) changes from plastic to liquid. In some embodiments, the liquid limit may be calculated using the ASTM standard test method D4318, the Casagrande test, and/or the fall cone test (also called the cone penetrometer test).
The calculated values of the Atterberg limits may have a close relationship between properties of a soil, e.g., compressibility, permeability, and strength. Accordingly, the Atterberg limits may provide an indication of the subsurface soil forces that a subsurface structural element may incur.
Other engineering properties of a soil may also be strongly correlated with indices that may be derived using the Atterberg limits. For instance, the indices may include a plasticity index (PI), a liquidity index (LI), and/or a consistency index (CI).
The plasticity index may be a measure of the plasticity of a soil. The plasticity index may calculated as the difference between the liquid limit and the plastic limit: PI=LL−PL. Low plasticity index soils tend to be silt, while high plasticity index soils tend to be clay. Soils with a plasticity index of zero (non-plastic) tend to have little or no silt or clay.
The liquidity index may be a used for scaling the natural water content of a soil sample to the limits. For instance, the liquidity index may be calculated as a ratio between (1) the difference between natural water content and plastic limit and (2) the difference between liquid limit and plastic limit: LI=(W−PL)/(LL−PL), where W is the natural water content.
The consistency index may indicate the firmness (or consistency) of a soil. For instance, the consistency index may be calculated as a ratio between (1) the difference between liquid limit and natural water content and (2) the difference between liquid limit and plastic limit: CI=(LL−W)/(LL−PL), where W is the natural water content.
Furthermore, the activity (A) of a soil may be the plasticity index divided by the percent of clay-sized particles (e.g., particles that are less than 2 micrometers in size) present. The dominant clay type that is present in a soil may be determined based on the activity of the soil. With a high activity soil, the soil may experience a large volume change when wetted and large shrinkage when dried.
In some embodiments, the design variables may be determined based at least in part on the plasticity index, the liquidity index, the consistency index, and/or the activity of a soil.
The order of the blocks of the methods may be changed, and various elements may be added, reordered, combined, omitted, modified, etc. Various modifications and changes may be made as would be obvious to a person skilled in the art having the benefit of this disclosure. The various embodiments described herein are meant to be illustrative and not limiting. Many variations, modifications, additions, and improvements are possible. Accordingly, plural instances may be provided for components described herein as a single instance. Boundaries between various components and operations are somewhat arbitrary, and particular operations are illustrated in the context of specific illustrative configurations. Other allocations of functionality are envisioned and may fall within the scope of claims that follow. Finally, structures and functionality presented as discrete components in the example configurations may be implemented as a combined structure or component. These and other variations, modifications, additions, and improvements may fall within the scope of embodiments as defined in the claims that follow.
This application is a continuation of U.S. patent application Ser. No. 15/400,837, filed Jan. 6, 2017, which claims benefit of priority of U.S. Provisional Application Ser. No. 62/276,018 entitled “SYSTEMS, METHODS AND APPARATUS FOR CREATING SUBSURFACE FOUNDATION CONCRETE BEAMS THAT REDIRECT THE FORCES GENERATED BY EXPANSIVE SOILS AND CLAYS THUS MINIMIZING FOUNDATION AND STRUCTURAL DAMAGE”, filed Jan. 7, 2016, the content of which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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62276018 | Jan 2016 | US |
Number | Date | Country | |
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Parent | 15400837 | Jan 2017 | US |
Child | 16171300 | US |