Patent Publication Number: US-2021189679-A1

Title: Systems and methods for supporting a structure upon compressible soil

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to ground improvements. In particular, the present disclosure relates to ground improvements that comprise at least one apparatus, at least one system and at least one method for supporting structures upon compressible soil. 
     BACKGROUND 
     A common method of ground improvement is the use of rigid inclusions. Traditional rigid inclusions are high modulus grout or cemented aggregate elements that are used to reinforce compressible soils and increase the load-bearing capacity of said soils by transferring loads to a firm, underlying stratum or bearing layer. Unlike piles, rigid inclusions do not have direct structural connections to any footings or other structures above them. If the stratum close to the surface is inadequate at transferring the load to the rigid inclusion therebelow, load transfer platforms or layers may be useful. 
     Typically, rigid inclusions are installed using a tool that forms an elongate hole within the ground and then injects the grout or cement aggregate mixture into the hole. The stabilizing performance of a rigid inclusion may be increased by increasing the diameter of the rigid inclusion within the load transfer platform and within the bearing layer. However, these known installation methods create rigid inclusions with a constant diameter along its length. Therefore, as a rigid inclusion is made larger, costs can increase without any increase in stabilizing performance Additionally, rigid inclusions require extensive time to reach full design strength and generally cannot easily be installed in rain or extreme cold conditions. Rigid inclusions have other shortcomings, such as when cement is used this can result in increased carbon dioxide production. Furthermore, rigid inclusions can only be removed by large-scale excavation. 
     Because of the many limitations of existing grout and cemented rigid inclusions, improved methods of reinforcing compressible soil may be desirable. 
     SUMMARY 
     Embodiments of the present disclosure relate to at least one apparatus, at least one system and at least on method for reinforcing a compressible soil stratum. 
     Some embodiments of the present disclosure relate to a helical rigid-inclusion that comprises an elongate body, a top member secured to one end of the elongate body, and at least one lower helically-formed member secured to an end of the elongate body, opposite to the top member. The top member may be helically arranged about the one end of the elongate body or the top member may be substantially planar. 
     Some embodiments of the present disclosure relate to a system that comprises at least one helical rigid-inclusion that comprises an elongate body, a top member secured to one end of the elongate body, and at least one lower helically-formed member secured to an end of the elongate body, opposite to the top member. The system may further comprise a load transfer platform configured to transfer at least a portion of a load force generated from an object resting upon an overlying surface to the at least one helical rigid-inclusion. In some embodiments of the present disclosure, the system further comprises an extension member that is reversibly connectible to the at least one helical rigid-inclusion, and a second at least one helical rigid-inclusion that is reversibly connected to the second elongate body. 
     Some embodiments of the present disclosure relate to a system that includes more than one helical rigid-inclusion that are arrangeable in an array. The array can be of various dimensions and shapes (from a top-plan view) depending upon the design and specifications of the structure that will be supported by the array. 
     Some embodiments of the present disclosure relate to a method of installing a system for reinforcing compressible soil. The method comprises the steps of: positioning a rotary drive mechanism above a surface at a desired location for installing a helical rigid-inclusion; attaching the helical rigid-inclusion to the rotary drive mechanism; exerting a torsional force from the rotary drive mechanism into the helical rigid-inclusion to initiate downward advancement below the surface; disconnecting the helical rigid-inclusion from the rotary drive mechanism and retracting the rotary drive mechanism to a location above the surface; repeating the previous steps until each helical rigid-inclusion is installed in a desired array; and installing a load transfer platform above the compressible soil, the load transfer platform configured to transfer a load force generated from an object resting on the surface to the helical rigid-inclusions of the array below the surface. 
     Without being bound by any particular theory, the embodiments of the present disclosure may reduce the “negative skin friction” or “downdrag” force experienced by existing rigid inclusions. Existing rigid inclusions may have a relatively large diameter and a comparatively high friction coefficient due to the gout/concrete column. In contrast, embodiments of the present disclosure relate to rigid inclusions with a relatively smaller diameter and a lower adhesion with the surrounding soil. The embodiments of the present disclosure can also reduce the cost and increase installation efficiencies compared to existing rigid inclusion processes in part because specialized equipment are not required for installation. The rigid inclusions of the present disclosure are configured to transfer the force of a load to a more rigid bearing layer therebelow rather than allowing the force to be transferred to a compressible layer, which could result in excessive settlement or instability. Furthermore, the embodiments of the present disclosure relate to arrays of rigid inclusions that can be arranged in arrays to provide greater support objects of various shapes and sizes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features of the present disclosure will become more apparent in the following detailed description in which reference is made to the appended drawings. The appended drawings illustrate one or more embodiments of the present disclosure by way of example only and are not to be construed as limiting the scope of the present disclosure. 
         FIG. 1  shows a side elevation view of two helical rigid-inclusions for use with ground improvement systems, according to embodiments of the present disclosure, wherein  FIG. 1A  shows a first helical rigid-inclusion; and  FIG. 1B  shows a second helical rigid-inclusion. 
         FIG. 2  shows a ground improvement system, according to embodiments of the present disclosure. 
         FIG. 3  shows an extension member for use with a helical rigid-inclusion, according to embodiments of the present disclosure, which can be used to extend the effective length of the helical rigid-inclusion to a target depth. 
         FIG. 4  shows a ground improvement system, according to embodiments of the present disclosure, wherein the helical rigid-inclusions include the extension member shown in  FIG. 3 . 
         FIG. 5  shows a ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array of helical rigid-inclusions, wherein  FIG. 5A  is a top-plan view of the system; and,  FIG. 5B  is a bottom plan view taken through line  4 - 4  of  FIG. 4 . 
         FIG. 6  shows another ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array of helical rigid-inclusions, wherein  FIG. 6A  is a top plan view of the system;  FIG. 6B  is a side-elevation view of the system wherein; and,  FIG. 6C  is a side-elevation view of the system, wherein the helical rigid-inclusions are battered at an angle from true vertical. 
         FIG. 7  shows another ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array and a sub-array of helical rigid-inclusions, wherein  FIG. 7A  is a top plan view of the system; and,  FIG. 7B  is a cross-sectional view of the system taken through line  7 - 7  of  FIG. 7A . 
         FIG. 8  shows another ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array and a sub-array of helical rigid-inclusions, wherein  FIG. 8A  is a top plan view of the system; and,  FIG. 8B  is a cross-sectional view of the system taken through line  8 - 8  of  FIG. 8A . 
         FIG. 9  shows another ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array of helical rigid-inclusions, wherein  FIG. 9A  is a top plan view of the system; and,  FIG. 9B  is a cross-sectional view of the system taken through line  9 - 9  of  FIG. 9A . 
         FIG. 10  shows another ground improvement system, according to embodiments of the present disclosure, wherein the system comprises an array of helical rigid-inclusions, wherein  FIG. 10A  is a top plan view of the system; and,  FIG. 10B  is a cross-sectional view of the system taken through line  10 - 10 . 
         FIG. 11  shows a side elevation view of the helical rigid-inclusion from  FIG. 1A , according to a further embodiment of the present disclosure. 
         FIG. 12  shows a drive tool, according to embodiments of the present disclosure, for use with various of the helical rigid-inclusions shown herein, wherein  FIG. 12A  shows a side elevation view of the drive tool; and,  FIG. 12B  shows a lower isometric view of the drive tool with a helical rigid-inclusion. 
         FIG. 13  shows a logic process flow of a method of installing the ground improvement system, according to embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Definitions 
     Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. 
     As used herein, the term “about” refers to an approximately +/−10% variation from a given value. It is to be understood that such a variation is always included in any given value provided herein, whether or not it is specifically referred to. 
     Embodiments of the present disclosure will now be described with reference to  FIG. 1  through  FIG. 13 , which show apparatus, systems and methods for supporting structures upon weak, compressible soil. 
       FIG. 1A  shows one embodiment of a helical rigid-inclusion  10  apparatus that may be used in ground improvement systems of the present disclosure. The helical rigid-inclusion  10  comprises an elongate body  12  with a first end  12 A and an opposite second end  12 B. Upon insertion into the ground, the first end  12 A may define a top end that is closer to the surface and the second end  12 B may define a second end that is further from the surface. The helical rigid-inclusion  10  may further comprise a top member  14  that is secured to the first end  12 A of the elongate body  12 , and at least one second lower helically-formed member  16  that is secured to the second end  12 B of the elongate body  12  that is opposite to the top member  14 . The elongate body  12  may have a cross-sections shape that is round, square, or another suitable shape and the elongate body  12  may be substantially hollow, or not. In some embodiments of the present disclosure, the elongate body  12  has a circular cross-sectional shape with an outer diameter ranging from about 1.5 inches to about 18 inches (note, one inch is equal to about 2.54 centimeters and one foot is equal to 12 inches). In some embodiments of the present disclosure, the elongate body  12  has an outer diameter of about 7 inches. The elongate body  12 , when substantially hollow, can have a wall thickness of about 0.1 inches to about 1.2 inches. In some embodiments of the present disclosure, the wall thickness of the elongate body  12 , when substantially hollow, is about 0.362 inches. In some embodiments of the present disclosure, the elongate body  12 , the top member  14  and the at least one lower helically-formed member  16  are made of steel; however, other materials with similar physical properties may be suitable also. In some embodiments of the present disclosure, the top member  14  and the at least one lower helically-formed member  16  may be secured to the elongate body  12  by welding or other known techniques. 
     In some embodiments of the present disclosure, the top member  14  and the at least one lower helically-formed member  16  are secured to the elongate body  12  in a configuration so that they both trace along the same cut line into the soil thereby minimizing soil disturbance when advancing the helical rigid-inclusion  10  into and through the soil. For example, the top member  14  and the lower member  16  may be configured at an equal pitch as measured by the vertical distance from a leading edge to a trailing edge of the top member  14 . In some embodiments of the present disclosure, the top member  14  and the at least one lower helically-formed member  16  are positioned along the elongate body  12  at increments that are evenly divisible by the desired pitch. In some embodiments of the present disclosure, the end of the elongate body  12  that leads the advancement below the surface may be beveled or otherwise pointed so as to facilitate inserting the helical rigid-inclusion  10  into the ground. 
     The diameter of the top member  14  may be selected to support a portion of a load force that is generated by an object  102  that is supported upon the surface  101  (shown in  FIG. 2 ). In some embodiments of the present disclosure, the top member  14  and the at least one lower helically-formed member  16  can have a diameter ranging from about 7 inches to about 45 inches and a thickness of about 0.2 inches to about 2 inches. In some embodiments of the present disclosure, the top member  14  and the at least one lower helically-formed member  16  have a diameter of about 20 inches and a thickness of about 0.625 inches. The top member  14  and the at least one lower helically-formed member  16  can be substantially the same dimensions, or not. 
     As illustrated in  FIG. 1A , in some embodiments of the present disclosure, the at least one lower helically-formed member  16  is a single helically formed member configured to cut through the soil at a constant pitch. In other embodiments of the present disclosure, the at least one lower helically-formed member  16  can be 2, 3 or more helically-formed members configured to cut through the soil at a constant pitch.  FIG. 1B  shows another embodiment of a helical rigid-inclusion  10 ′ that includes multiple lower helically-formed members  16 . If there are more than one lower helically-formed members  16 , they can be substantially the same dimensions, or not. The person skilled in the art will appreciate that the references below to the helical-rigid inclusion  10  are also references to the helical rigid-inclusions  10 ′. 
       FIG. 2A  shows a ground improvement system  100  according to embodiments of the present disclosure. The system  100  comprises at least one helical rigid-inclusion  10  and the object  102 , wherein the object  102  is positioned upon and at least partially supported by the surface  101  that is located above a compressible layer  104 . Although  FIG. 2  shows three helical rigid-inclusions  10 , as discussed further below, the present disclosure is not limited to this number. In some uses of the system  100 , the object  102  is a building, a structure, a warehouse, a road-supporting embankment, a support structure for a bridge, a tank and the like. The object  102  may generate a constant load force, a transient load force, or a combination of both. The load force generated by the object  102  may be focused in a specific area or it may be diffused across a broader area or the object  102  may generate more than one load force for example if the object  102  is a warehouse and the contents of the warehouse are concentrated within an area therein. The object  102  can have a footprint of between about 110 square feet to about 1,000,000 square feet, or larger (a foot is equal to 12 inches). As will be appreciated by those skilled in the art, the size and shape of the object  102  can determine the number of the helical rigid-inclusions  10  used and the arrangement of the helical rigid-inclusions  10  used, which is referred to herein as an array. The array can be designed to be circular, rectangular, square, or any shape (form a top-plan view) and include a distribution of helical rigid-inclusions  10  that are desired to support the object  102  upon the surface  101  and the compressible layer  104  therebelow. The helical rigid-inclusions  10  are configured to transfer at least a portion of the load force generated by the weight of the object  102  upon the surface  101  to the bearing layer  106  through the helical rigid-inclusions  10 . In some embodiments of the present disclosure, this transfer of at least a portion of the load force to the bearing layer  106  may partially, or substantially completely, bypass transferring any of the force to the compressible layer  104 . This transfer of at least a portion of the force to the bearing layer  106  provides greater stability of the object  102  upon the surface  101 . 
     In some embodiments of the present disclosure, the object  102  may be on a shallow foundation (e.g. concrete footings), or not. In some embodiments of the present disclosure, the object  102  may be positioned upon a concrete slab-on-grade, or not. 
     In some embodiments of the present disclosure, the system  100  further comprises a load transfer platform  108  that is positioned between the compressible layer  104  and the object  102 . The load transfer platform  108  may be useful when the stratum close to the ground surface is of insufficient integrity or physical strength to support the object  102 . In some embodiments of the present disclosure, the load transfer platform  108  may have a thickness of between about 1 foot and about 5 feet. In some embodiments of the present disclosure, the load transfer platform  108  comprises a form of a compacted granular material. In some embodiments of the present disclosure, the compacted granular material is gravel, recycled asphalt, other suitable materials, or combinations thereof. In some embodiments of the present disclosure, the load transfer platform  108  further comprises layers of embedded geotextile, geosynthetic material, steel mesh reinforcement, or a combination thereof. 
     In some instances, the compressible layer  104  can be of such a thickness that the bearing layer  106  is at a depth that exceeds the length of the at least one helical rigid-inclusion  10 . In these instances, the helical rigid-inclusion  10 / 10 ′ may further comprise an extension member  20  (as shown in  FIG. 3 ) that is connectible to both a downward facing end of an upper helical rigid-inclusion member  11 A and an upward-facing end of a lower helical rigid-inclusion member  11 B. In some embodiments of the present disclosure, the extension member  20  comprises a central shaft  22 , which may be substantially hollow or not, and a sleeve  24  located at one end of the hollow central shaft  22 . The sleeve  24  defines at least one aperture  26  that can be used to connect the extension member  20  to the upward-facing end of the lower helical rigid-inclusion member  11 B. The central shaft  22  comprises at least one aperture  28  at an end opposite the sleeve  24  that can be used to connect the extension member  20  to the downward-facing end of upper helical rigid-inclusion member  11 A for example by inserting one or more connection members through the at least one apertures  26 ,  28 . As will be appreciated by those skilled in the art, the extension member  20  can be connected to the upper member  11 A and the lower member  11 B by various other approaches and methods. In some embodiments of the present disclosure, the extension member  20  is made of steel or another material of similar physical properties. 
     The extension member  20  can be connected to the at lower helical rigid-inclusion member  11 B when the lower helical rigid-inclusion member  11 B has already been installed below ground, or not. 
       FIG. 4  shows a ground improvement system  100 ′ that includes multiple helical rigid-inclusions  10  that each comprise the extension member  20 , wherein the object  102  is located above a compressible layer  104 ′ that has such a thickness that extensions  20  are used. Each of helical rigid-inclusions  10  and each extension member  20  are designed to support at least a portion of the object  102  by transferring to the bearing layer  106  at least a portion of the load force generated by the object  102  upon the load transfer platform  108 . In some embodiments of the present disclosure, the distance between the surface and the bearing layer  106  may necessitate more than one extension  20  being used for each helical rigid-inclusion  10 . For example, at least two, or three or more extension members  20  can be used to reach, or exceed, a total length about 30 feet, or less. The person skilled in the art will appreciate that the references below to the system  100  may also include references to the system  100 ′. 
       FIG. 5A  shows a top plan view of the system  100  from  FIG. 3 . In this non-limiting view, the load transfer platform  108  is shown has having a larger foot print than the object  102 . The person skilled in the art will appreciate that the load transfer platform  108  may also have a footprint of substantially the same size, or smaller, than the footprint of the object  102 .  FIG. 5B  shows the second end  12 B of a number of helical rigid-inclusions  10 . From this view, it is apparent that the system  100  may include an array  401  that comprises one or more columns  400  of helical rigid-inclusions  10  and one or more rows  402  of helical rigid-inclusions  10 . In the non-limiting example of  FIG. 5B , three columns  400 A,  400 B and  400 C are shown and three rows are shown  402 A,  402 B and  402 C. The number of columns  400  and rows  402  that are utilized and the total number of rigid helical inclusions  10  used may depend on a variety of factors, including, but not limited to: the mass of the object  102 , the footprint of the object  102 , the mass of the load transfer platform  108 , the foot print of the load transfer platform  108 , the depth of the compressible layer  104 , the compressibility of the compressible layer  104 , the stability of the bearing layer  106 , the local climate and freeze/thaw cycles and combinations thereof. Furthermore, while  FIG. 5B  shows the array  401  as being arranged in an equal number of columns  400  and rows  402 , that is not a requirement so long as the system  100  can provide support the object  102 , which may be of various shapes and footprints, when viewed from above. 
       FIG. 6  shows a ground improvement system  600  that comprises an array  300  of multiple helical rigid-inclusions  10  according to embodiments of the present disclosure.  FIG. 6A  shows a top-plan view of the system  600  wherein the array  300  comprises multiple helical rigid-inclusions  10  are arranged to define multiple circles. As will be appreciated by those skilled in the art, the array  300  comprises one single circle or there may be multiple circles of helical rigid-inclusions  10 . In some embodiments of the present disclosure, the distance between helical rigid-inclusions  10  along the curvature of each circle&#39;s circumference may be between about 5 feet and about 20 feet. In some embodiments of the present disclosure, the distance may be between about 8 feet and about 12 feet. In some embodiments of the present disclosure, the distance is about 8 feet. The person skilled in the art will appreciate that the distance between each of the circles need not be equal nor are the circles required to be concentric. Furthermore, the positioning of the multiple helical rigid-inclusions  10  on each circle of the array  300  may be evenly spaced about the circumference, or not, and each circle may have the same number of helical rigid-inclusions  10 , or not. 
       FIG. 6B  shows a side elevation view of the system  600  comprising the array  300  with multiple helical rigid-inclusions  10  arranged to define the circumference of multiple circles. In some embodiments of the present disclosure, the multiple helical-rigid inclusions  10  are installed in a substantially vertical orientation.  FIG. 6C  shows another embodiment of the present disclosure wherein at least some of the helical rigid-inclusions  10  within the array  300  are battered at an angle from true vertical. The battering of the helical rigid-inclusions  10  will increase their lateral load bearing capacity if lateral load forces are anticipated to be exerted upon the object  102 . In some embodiments of the present disclosure, the object  102  supported by the system  600  may be a tank or equivalent storage structure. In some embodiments of the present disclosure, the diameter of the object  102  may be about 50 feet to about 400 feet. In some embodiments of the present disclosure, the diameter of the object  102  may be about 100 feet to about 175 feet. In some embodiments of the present disclosure, the diameter of the object  102  may be about 120 feet to about 150 feet. 
       FIG. 7  shows a ground improvement system  700  that comprises multiple helical rigid inclusions  10  arranged in an array  302  and a sub-array  302 A.  FIG. 7A  is a plan view of a non-limiting example of the system  700 . In some embodiments of the present disclosure, the array  302  comprises multiple helical rigid-inclusions  10  arranged to define a rectangle and the multiple rigid-inclusions  10  arranged within the sub-array  302 A may also define a rectangle. The multiple helical rigid-inclusions  10  of the sub-array  302 A may be arranged at a distance to support a localized object  102 ′ within the array  302 . In some embodiments of the present disclosure, the helical rigid-inclusions  10  of the array  300  in the system  700  may be arranged in paired rows. In some embodiments of the present disclosure, each row of the paired rows may be arranged on either side of a centerline of a shallow foundation  103 . In some embodiments of the present disclosure, the shallow foundation is a strip-footing. In some embodiments of the present disclosure, the distance between the multiple helical rigid-inclusions  10  of the array  302  and the sub-array  302 A may be about 5 feet and about 20 feet. In some embodiments of the present disclosure, the distance between the multiple helical rigid-inclusions  10  of the system  700  may be between about 8 feet and about 15 feet. In some embodiments of the present disclosure, the distance between the multiple helical rigid-inclusions  10  of the array  302  is about 12 feet and distance between the multiple helical rigid-inclusions  10  of the sub-array  302 A is about 8 feet. The person skilled in the art will appreciate that the distance between each of the paired rows of helical rigid-inclusions  10 , in either the array  302  or the sub-array  302 A need not be equal. Furthermore, the multiple helical rigid-inclusions  10  may be evenly spaced about the perimeter, or not.  FIG. 7B  shows a cross-section view of the system  700 . In some embodiments of the present disclosure, the object  102  may be a building or any other structure with a shallow foundation. In some embodiments of the present disclosure, the localized object  102 ′ can be a storage rack, a machine, or any other object that is concentrated in a defined area. 
       FIG. 8A  and  FIG. 8B  show a ground improvement system  800  that is similar to the system  700 . At least one difference is that the array  300  comprises a single line of multiple helical rigid-inclusions  10  arranged to define a rectangle. In the non-limiting example of the system  800 , the helical rigid-inclusions  10  may be arranged at a location substantially directly below a centerline of a shallow foundation. 
     In some embodiments of the present disclosure, the shallow foundation is a strip-footing. 
       FIG. 9  shows a ground improvement system  900  that comprises multiple helical rigid inclusions  10  arranged in an array  304 .  FIG. 9A  shows a plan view of the array  304  comprising multiple helical rigid-inclusions  10  arranged at a distance in rows and columns to define a rectangle. In some embodiments of the present disclosure, the distance between the helical rigid-inclusions  10  may be between about 5 feet and about 20 feet. In some embodiments of the present disclosure, the distance between the helical rigid-inclusions  10  may be between about 8 feet and about 15 feet. In one embodiment of the present disclosure, the distance between the helical rigid-inclusions  10  is about 10 feet. The person skilled in the art will appreciate that the distance between the helical rigid-inclusions  10  within each of the rows (or columns) need not be equal. Furthermore, the positioning of the multiple helical rigid-inclusions  10  may be evenly spaced about the perimeter, or not.  FIG. 9B  shows an elevation view of an embodiment of the system  900 , wherein the object  102  comprises a concrete foundation  40 . In some embodiments of the present disclosure, the object  102  is a warehouse or similar structure. In some embodiments of the present disclosure, the concrete foundation  40  is slab-on-grade  40   a . In some embodiments of the present disclosure, the array  300  extends past the perimeter of the object  102 . 
       FIG. 10A  shows a ground improvement system  1000  that comprises an array  306  of multiple helical rigid-inclusions  10 . The array  306  is configured to support an object  1002 , such as a roadway, highway, freeway, toll-road and the like, that is positioned above a compressible layer  104  (see  FIG. 10B ). The array  306  is also configured to support another object  1004 , such as an embankment or other formation made of soil, rock or recycled materials, which may include within it a layer or multiple layers of geotextile, geosynthetic material, steel reinforcement mesh or combinations thereof. The multiple helical rigid-inclusions  10  of the array  306  can be arranged to accommodate the positioning, size and path of travel of the object  1002 . In some embodiments of the present disclosure, the system  1000  comprises multiple sub-arrays which use varying HRI configurations and spacings to suit the different loading conditions which may occur at various areas of the footprint of the object  1002 . For example, if the design height of an embankment becomes greater along its path of travel, so too may the load force generated be increased. This increased load force may require the helical rigid-inclusions  10  in that area of the embankment&#39;s footprint to have a greater load capacity or to be more closely spaced, or, a load transfer platform  108  may be incorporated or altered to provide better load transfer to the helical rigid inclusions  10 . Sub-array&#39;s  306 A,  306 B,  306 C and  306 D are shown to illustrate the possibility of using multiple different helical rigid inclusion designs or spacings to suit different loading conditions which may exist within a common structure or embankment object  1002 . 
       FIG. 11  shows another non-limiting example of a helical rigid-inclusion  10  with a top member  14 A that defines opposite planar surfaces that are arranged to extend substantially perpendicular from a longitudinal axis of the elongate body  12  (see line X in  FIG. 1A  and  FIG. 11 ). The skilled person will appreciate that the top member  14 A may also be used with the other embodiments of helical rigid-inclusions described herein above. The top member  14 A may be operatively coupled to the first end  12 A of the elongate body  12  by one or more connection members, such as a pin, bolt, shank or other type of connection member that can operatively couple the top member  14 A to the first end  12 A. In some embodiments of the present disclosure, the top member  14 A can be operatively coupled to the first end  12 A by an extension member (not shown) that extends substantially perpendicular from one of the planar surfaces of the top member  14 A for receipt within or about the second end  14 A. Alternatively, the second end  12 A may include a sleeve (not shown) that can be received by a portion of the top member  14 A. In some embodiments of the present disclosure, the top member  14 A may be positioned upon the first end  12 A and not directly connected thereto. For example, if the helical rigid-inclusion  10  is already positioned within the soil with a least a portion of the first end  12 A proximal to the surface  101  and before when a load transfer platform  108  is deployed, the top member  14 A may be placed upon the first end  12 A and the load transfer platform  108  can be deployed thereupon. 
       FIG. 12A  shows one example of a drive tool  2000  that may be used for installing and removing the helical rigid-inclusions  10  of the present disclosure. The drive tool  2000  comprises a top plate  2002 , a shank  2004  and an engaging member  2006  that is arranged about the shank  2004  below the top plate  2002 . The top plate  2002  is configured to operative couple with a rotary drive mechanism of the equipment being used to install (and remove) the helical rigid-inclusion  10  so that rotating the rotary drive mechanism causes the drive tool  2000  to rotate also. The shank  2004  is connected at one end to the top plate and extends away substantially perpendicular from the top plate  2002 . The shank  2004  defines a tip  2008  that is opposite to the top plate  2002 . The tip  2008  may be frustoconcial, or otherwise shaped to facilitate entry of the shank  2004  into the first end  12 A of the helical rigid-inclusion  10  (as shown in  FIG. 12B ). 
     The engaging member  2006  is also connected at one end to the top plate  2002  and extends away therefrom, about the shank  2004 . The engaging member  2006  defines a slot  2010  and a shoulder  2012 . The slot  2010  extends in a helical path about the shank  2004  between proximal to the tip  2008  and proximal to the top plate  2002 . The shoulder  2012  is positioned at the end of the slot  2010  that is proximal to the top plate  2002 . 
       FIG. 13  shows a sequence of steps that make up a method  200  of installing a ground improvement system of the present disclosure. 
     The method  200  comprises a step  201  of attaching the helical rigid-inclusion  10  to a rotary drive mechanism that may be attached to a hydraulic excavator or to another piece of construction equipment with similar functionality. The helical rigid-inclusion  10  can be attached to the rotary drive mechanism by use of the drive tool  2000 . In use, the drive tool  2000  is positioned proximal the first end  12 A of the helical rigid-inclusion  10  and the drive tool  2000  is then moved so that the tip  2008  is received within the first end  12 A. Next the rotary drive mechanism can rotate until a trailing edge  14 C of the top member  14  is received within the slot  2010 . Continued rotation of the drive tool  2000  causes the top member  14  to move through the slot  2010  until the trailing edge  14 C abuts the shoulder  2012 . At that position, further rotation of the drive tool  2000  will rotate the entire helical rigid-inclusion  10 . In other embodiments of the present disclosure, another form of drive tool may be used that is received about the first end  12 A (rather than within) of the helical rigid-inclusion  10 . 
     Step  202  comprises positioning a rotary drive mechanism above a surface at a desired location for installing a helical rigid-inclusion  10 . 
     Step  203  comprises exerting a torsional force from the rotary drive mechanism into the helical rigid-inclusion  10  to initiate rotation and downward advancement of the helical rigid-inclusion  10  below the surface. In some embodiments of the present disclosure, the torsional force may be applied by bearing against the trailing edge  14 C of the top member  14 . 
     The method  200  further comprises a step  204  of advancing the helical rigid-inclusion  10  through the compressible layer  104  to the bearing layer  106  using the torsional force and a downward linear force. In some embodiments of the present disclosure, the downward linear force may be exerted by the hydraulic excavator or another piece of construction equipment. 
     Step  205  comprises disconnecting the helical rigid-inclusion from the rotary drive mechanism and retracting the rotary drive mechanism to a location above the surface. 
     Step  206  of the method further comprises repeating steps  201  to steps  205  until all of the desired helical rigid-inclusions  10  of the ground improvement system  100  are installed in order to support the object  102  or a portion thereof. 
     Step  207  comprises installing the load transfer platform  108  above the compressible layer  104 , the load transfer platform  108  is configured to transfer a force exerted by the object  102  upon the surface, or a portion thereof, to the helical rigid-inclusions  10  therebelow. 
       FIG. 11  also shows an optional step  210  of coupling an extension member  20  to an upper portion of the helical rigid-inclusion  10  that is at least partially below the surface, or not. Step  210  can be useful when the depth of the compressible layer  104  exceeds the length of each helical rigid-inclusion  10  used in the system  100 . The method  200  may also further comprise a step of repeating steps  201  to  206  (and optionally step  207 ) so as to form an array of helical rigid-inclusions  10 , where such array is configured to support an object and/or any resulting lateral load forces that the object exerts upon a compressible layer.