Patent Publication Number: US-8113744-B2

Title: Jetting system for foundation underpinning

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     None. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates generally to an apparatus and methods for foundation underpinning. More particularly, the invention relates to an apparatus and method for employing a foundation piling system to support and level an existing building foundation. 
     2. Background of the Invention 
     Several methods and systems have been developed and used for lifting, leveling and stabilizing above-ground structures such as buildings, slabs, walls, columns, etc. One conventional technique employs a stack, or pile, of pre-cast concrete pile segments that is positioned underneath, and supports, the structure to be stabilized and leveled. Typically, a hole is dug underneath the structure to a depth slightly greater than the length of a pile segment. Multiple pile segments are then driven into the ground one on top of the other until a particular depth is reached, thereby forming a vertical stack, or pile, of the pile segments. The pile segments are driven into the ground until a rock strata is encountered, or until the resulting pile is believed to be sufficiently deep to adequately support the structure. In situations where a rock strata cannot be reached, the pile segments are driven to a depth great enough to cause sufficient friction between the earth and the outer surfaces of the pile to prevent substantial vertical movement of the pilings. A jack is next positioned on the upper surface of the pile, between the uppermost pile segment and the structure. Finally, the structure is raised to the desired height. 
     There are several disadvantages to this conventional technique. Other than being stacked one on top of another, the concrete segments are typically not connected. Thus, the individual pile segments may become misaligned during installation. In some cases, substantial misalignment can negatively impact the stability and strength of the entire pile. In addition, determining the installed pile depth typically requires monitoring the quality and number of pre-cast concrete segments used to form the pile. Further, in most cases, the completed pile is not reinforced. Over time, the cyclical shrinking and swelling of the soil surrounding the piles can cause shifting of individual pile segments, potentially resulting in misalignment and weakening of the pile. Still further, the individual pre-cast pile segments are often cylindrical in shape. As each pile segment is driven into the ground, the entire outer radial surface of each pile engages the surrounding earth, resulting in relatively large frictional forces which can inhibit continued advancement of the individual pile into the ground. 
     Another conventional method utilizes a flexible cable to lock the individual pile segments together as a unit, thereby reducing misalignment of the concrete segments. A typical example of this methodology is found in U.S. Pat. No. 5,288,175. A starter concrete pile segment with a high strength steel cable anchored to and extending from the center of the starter segment is first driven into the soil beneath the foundation using a hydraulic jack. Multiple concrete segments, each having a central throughbore, are then sequentially threaded onto the cable and driven into position, each one on top of the other to form the complete pile that is used to support and level the structure. The cable is intended to promote vertical alignment of the pile segments. It also permits pile penetration depth to be determined, either by reading a strand marker or calculating it by measuring the length of cable used to lock the pile together. 
     In an effort to drive the individual pile segments deeper to achieve a more stable pile, and to reduce the time required to drive the pile segments, some conventional underpinning methods jet or spray a fluid into the soil beneath the lowermost pile segment. A typical example of this installation method is found in U.S. Pat. No. 5,399,055. Similar to other conventional methods, the individual pre-cast concrete segments are pressed or driven vertically into the soil using a hydraulic jack. When the concrete segments cannot be driven further, fluid is injected downward through holes formed in the concrete segments. The fluid moistens and loosens the soil beneath the pile, allowing the pile to be driven deeper and to be driven deeper more easily than would have otherwise been possible. After discontinuing the fluid jetting, additional concrete segments are positioned on the pile and driven downward using the hydraulic jack. Fluid is again injected through the concrete segments once the pile cannot be driven further downward. After the fluid jetting is discontinued, additional concrete segments positioned on the pile and driven downward, and so on. This process is repeated until the desired pile depth is reached. To promote alignment of the concrete segments, a reinforcing rod may be inserted into the holes formed in the concrete segments. Finally, in some cases, grout is injected into the annulus formed between the outer surface of the reinforcing rod and the inner surface of the holes through the concrete pile segments in an effort to solidify the pile as a unitary structure. 
     These relatively advanced methods of fluid jetting, however, are not without disadvantages. In particular, alignment of the pile segments is not always assured. When the pile segments are driven in, they are in no way connected, such as by a cable or reinforcing rod. As a result of such misalignment, jetting fluid may not reach the base of the pile. Therefore, the soil beneath the pile may not be moistened by the jetting fluid, preventing the pile from being driven as deep as desired. Also as a result of pile segment misalignment, it may not be possible to later insert the reinforcing rod through the entire depth of the pile. Nor may it be possible to inject grout the full length of the pile. Thus, the pile may be misaligned as well as not reinforced over portions of its length. 
     Accordingly, there remains a need in the art for a foundation underpinning apparatus and methods that offer the potential to maintain the alignment of the individual pre-case pile segments forming a pile both during and after installation. Such a foundation underpinning would be particularly well received if it could be installed deeper and more efficiently than known installation methods permit. 
     BRIEF SUMMARY OF SOME OF THE PREFERRED EMBODIMENTS 
     A jetting system for installing a foundation underpinning is disclosed. In some embodiments, the jetting system includes a pile having one or more pile segments and a jetting tube. Each of the one or more pile segments includes a head, a trunk extending from the head, and a throughbore passing axially through the head and the trunk. The throughbore has a longitudinal centerline. The area of a cross-section through the head and normal to the centerline is greater than the area of a cross-section through the trunk and normal to the centerline. The throughbores of the one or more pile segments are vertically aligned forming a passage through the pile. The jetting tube has a first end with an outlet and a second end with an inlet. The first end of the jetting tube inserted into the passage. 
     Some methods of jetting in the foundation underpinning include positioning the first pile segment on soil beneath the foundation, inserting the first end of a jetting tube into the throughbore, and delivering fluid into the second end of the jetting tube, through the jetting tube, and out of the first end of the jetting tube to the soil. 
     Thus, embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with certain prior devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more detailed description of the preferred embodiments, reference will now be made to the accompanying drawings, wherein: 
         FIG. 1  is a front elevation view of an embodiment of an individual pile segment used to construct a pile in the ground; 
         FIG. 2  is a cross-sectional view of the individual pile segment of  FIG. 1 ; 
         FIG. 3  is a schematic view of two of the individual pile segments of  FIG. 1  being driven into the ground to form a pile; 
         FIG. 4  is a schematic view of an embodiment of a foundation underpinning including a plurality of the individual pile segments of  FIG. 1 ; 
         FIG. 5  is a logic flow diagram of a representative method to construct a pile of  FIG. 4 ; 
         FIG. 6  is a schematic view of a pile being constructed in accordance with the representative method of  FIG. 5 ; and 
         FIG. 7  is a logic flow diagram of a representative method to form a support base beneath the pile constructed according to  FIG. 5 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following discussion is directed to various embodiments of the invention. Although one or more of these embodiments may be preferred, the embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. In addition, one skilled in the art will understand that the following description has broad application, and the discussion of any embodiment is meant only to be exemplary of that embodiment, and not intended to intimate that the scope of the disclosure, including the claims, is limited to that embodiment. 
     Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. The drawing figures are not necessarily to scale. Certain features and components herein may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections. 
     Referring now to  FIGS. 1 and 2 , an embodiment of an individual pile segment  10  is illustrated. Pile segment  10  has a longitudinal axis  50 , and comprises a body  20  and a vertical throughbore  40  extending through body  20  generally parallel to axis  50 . In particular, throughbore  40  is centrally positioned, and shares the same axis  50  as pile segment  10 . Body  20  includes a trunk  28  and a head  30  disposed at the upper end of trunk  28 . In this embodiment, head  30  is integral with trunk  28 . 
     In this embodiment, trunk  28  is substantially cylindrical, having an outer radial or side surface  21  and a lower axial surface  22 . Trunk  28  has a height  25  measured substantially parallel to axis  50  and a diameter  26  measured substantially perpendicular to axis  50 . Thus, as used herein, the term “height” refers to dimensions and distances measured substantially parallel to the longitudinal axis of a body, while the terms “diameter” and “width” refer to dimensions and distances measured substantially perpendicular to the longitudinal axis of a body. Likewise, head  30  is substantially cylindrical, having an outer radial or side surface  31 , a lower annular axial surface  32 , and an upper axial surface  33 . Head  30  has a height  35  and a diameter  36 . Collectively, trunk  28  and head  30  define an overall height  12  of body  20  and pile segment  10 . 
     It should be appreciated that height  35  of head  30  is less than height  25  of trunk  28 , and further, diameter  36  of head  30  is greater than diameter  26  of trunk  28 . For reasons that will be explained in more detail below, the ratio of diameter  36  of head  30  to diameter  26  of trunk  28  is preferably greater than 1.0. 
     Since head  30  has a diameter  36  that is greater than the diameter  26  of trunk  28  in this embodiment, body  20  of pile segment  10  has a general “T-shaped” profile and cross-section as best seen in  FIG. 2 . In other words, a first cross-section through the head (e.g., head  30 ) and perpendicular to the pile segment axis preferably has a first cross-sectional area that is greater than a second cross-sectional area of a second cross-section taken through the trunk (e.g., trunk  28 ) perpendicular to the pile segment axis. For example, a first cross-section taken at a first plane  35  through head  30  and perpendicular to axis  50  has a first cross-sectional area that is greater than a second cross-sectional area of a second cross-section through trunk  28  taken at a second plane  25  perpendicular to axis  50 . 
     Although head  30  and trunk  28  are shown as cylindrical, in general, head  30  and trunk  28  may comprise any suitable shapes. For reasons that will be explained in more detail below, head  30  and trunk  28  are preferably configured and shaped such that any cross-section through head  30  is larger than any cross-section through trunk  28 . For instance, as shown in  FIGS. 1 and 2 , head  30  and trunk  28  may both be cylindrical, with head  30  having a larger diameter than trunk  28  (i.e., body  20  is “T-shaped”). As yet another example, body  20  may be conical, with the diameter of body  20  generally increasing from the lower trunk toward the upper head. 
     Pile segment  10  may comprise any suitable material including, without limitation, a metal, a metal alloy, a non-metal, a composite, or combinations thereof. However, pile segment  10  preferably comprises a relatively rigid material capable of withstanding compressional forces. Thus, concrete is a particularly suitable material for pile segment  10  since concrete is readily available, relatively cheap, and has suitable compressional strength. 
     Referring now to  FIG. 3 , two pile segments  10 , as previously described, are shown vertically stacked on each other and driven into the ground or soil  70  to form a pile or underpinning. For purposes of further explanation, pile segments  10  are assigned reference numerals  10 - 1  and  10 - 2 , there being a first or lower pile segment  10 - 1  and a second or upper pile segment  10 - 2  shown in  FIG. 3 . 
     Lower pile segment  10 - 1  is driven vertically into the ground in the direction of arrow  16  by a force  80 . Then, second pile segment  10 - 2  is placed on top of first pile segment  10 - 1 , and both first pile segment  10 - 1  and second pile segment  10 - 2  are driven into the ground together. In particular, pile segments  10 - 1  and  10 - 2  are vertically aligned, with axes  50  substantially aligned, as they are stacked on each other and driven into the ground  70 . In general, vertical alignment of pile segments (e.g., pile segments  10 - 1 ,  10 - 2 , etc.) that form a pile is preferred to promote stability and support. As used herein, the term “vertical” or “vertically” may be used to refer to the orientation of the axis of a body (e.g., axis  50  of pile segment  10 ), a force, or a direction, that is substantially perpendicular to the surface of the ground. Since pile segment  10 - 1  is first driven into the soil  70  followed by pile segment  10 - 2 , pile segment  10 - 1  may be described as the “leading” pile segment and second pile segment  10 - 2  may be described as a “trailing” pile segment. Likewise, since each pile segment  10 - 1 ,  10 - 2  is driven vertically into the ground with trunk  28  first, followed by head  30 , for a given pile segment  10 , trunk  28  may be described as “leading” and head  30  maybe described as “trailing.” 
     Pile segments  10 - 1  and  10 - 2  are driven vertically into the soil  70  in the direction of arrows  16  by force  80  applied to upper axial surface  33  of upper pile segment  10 - 1 . As pile segments  10 - 1  and  10 - 2  are vertically stacked and driven into the soil  70 , lower axial surface  22  of trunk  28  of trailing pile segment  10 - 2  engages, and transfers force(s)  80  to the upper axial surface  33  of head  30  of the leading pile segment  10 - 1 . Force  80  may be provided by any suitable device capable of driving a pile segment (e.g., pile segment  10 ) into the ground including, without limitation, a jack (e.g., a hydraulic jack, a mechanical jack, a pneumatic jack, etc.), an actuator, or combinations thereof. 
     Unlike pile segments  10 - 1 ,  10 - 2 , most conventional pile segments are cylinders having a constant or uniform diameter along their entire height. Consequently, when each such conventional pile segment is driven vertically into the ground, the entire outer radial surface of the cylinder engages the surrounding soil. As a result, frictional forces arise along the entire height of each such conventional pile segment (the first as well as each subsequent conventional pile segment driven into the soil). Such frictional forces resist continued advancement of the conventional pile segments into the ground, thereby increasing the time and forces required to sufficiently drive such conventional pile segments into the soil. 
     As shown in  FIG. 3 , each pile segment  10  includes an upper head  30  having a diameter  36  that is greater than the diameter  26  of its lower trunk  28 . Thus, pile segments  10  do not have a constant diameter or width along their entire heights. As a result, when leading pile segment  10 - 1  is driven vertically into the soil  70  in the direction of arrow  16 , both side surfaces  21 ,  31  engage the surrounding earth, generating functional forces therebetween. However, head  30  of leading pile segment  10 - 1  at least partially creates a pathway  71  for trailing pile segment  10 - 2 . The width or diameter of pathway  71  will be substantially the same as diameter  36  of the head  30  of leading pile segment  10 - 1 . Thus, as trailing pile segment  10 - 2  is stacked and driven into the soil  70 , side surface  31  of head  30  of trailing pile segment  10 - 2  engage the surrounding soil generating frictional forces therebetween. However, because head  30  of leading pile segment  10 - 1  has generated a bore greater than the diameter of side surface  21  of trunk  28  of trailing pile segment  10 - 2 , engagement between side surface  21  of trailing pile segments  10 - 2  is believed to be significantly reduced. Further, since height  35  of head  30  is relatively small, as compared to the overall height of a conventional cylindrical pile segment of similar size as pile segment  10 , the frictional forces acting on side surface  31  of trailing pile segment  10 - 2  act over a much smaller surface area than frictional forces acting on a conventional cylindrical pile segment. In general, the less contact between a pile segment (e.g., pile segment  10 - 2 ) and the surrounding soil, the faster and easier it is to drive the pile segment. Consequently, as compared to similarly sized conventional cylindrical pile segments whose entire outer radial surface engages the soil, embodiments of pile segment  10  offer the potential for increased driving speed and ease. It should be appreciated that the slope of the outer surface of leading pile segment  10 - 1  may be optimized to make the initial hole in the ground, as for example cone shaped instead of T-shaped. 
     After pile segments  10 - 1 ,  10 - 2  are driven to the desired depth, lower axial surface  22  and lower annular axial surface  32  of pile segments  10 - 1  provide bearing surface area to level and support a structure above pile segments  10 - 1 ,  10 - 2 . The surrounding soil  70  begins to collapse against side surface  21  of pile segment  10 - 2 . Over time, the space  72  between outer surface  21  of pile segment  10 - 2  and the outer edge of pathway  71 , between head  30  of pile segment  10 - 1  and head  30  of pile segment  10 - 2 , is filled in by the collapsing soil  70 . Once space  72  is filled in by soil  70 , pile segment  10 - 2  is laterally supported by soil  70 . Moreover, lower annular axial surface  32  of pile segment  10 - 2  engages soil  70  and provides additional bearing surface area. 
     Referring now to  FIG. 4 , an embodiment of a foundation underpinning  100  that supports and/or levels a structure  105  and its foundation or slab  110  is illustrated. It is to be understood that structure  105  may be a commercial or residential building, a new construction or an existing structure, a wall, a column, or any other structure requiring support, stabilization, leveling, or combinations thereof. Typically, but not necessarily, slab  110  is constructed of concrete. 
     Underpinning  100  comprises a stack or pile  111 , a cap  112 , and spacers  115 . Vertical pile  111  includes one or more individual pile segments  10  as previously described vertically aligned and stacked on each other within the surrounding soil  70 . Thus, as used herein, the term “pile” may be used to refer to a vertical stack of one or more individual pile segments (e.g., pile segments  10 ). Further, the term “pile” may be used to describe a vertical stack of one or more pile segments both during construction of an underpinning (i.e., while driving pile segments into the ground), and following completion of an underpinning. 
     Cap  112  and spacers  115  are positioned between pile  111  and slab  110 , and are supported from below by pile  111 . Cap  112  includes a throughbore  113 . Although a variety of other suitable shapes and materials may be employed, cap  112  preferably comprises a rigid rectangular concrete block and spacers  115  comprise rigid cylindrical pre-cast concrete segments (e.g., standard 6″ diameter concrete spacers). In addition, underpinning  100  further comprises one or more shims  155  positioned between each spacer  115  and slab  110 . In general, shims  155  ensure that the interface between the foundation underpinning  100  and the slab  110  is without “play”, meaning the fit between the foundation underpinning  100  and the slab  110  is so snug that foundation underpinning  100  is substantially held in place (i.e., no substantial movement) beneath and supporting the slab  110 . Shims  155  may be constructed of any suitable material, including without limitation, metals, metal alloys (e.g., steel), non-metals (e.g., wood, polymers, plastic), composites, or combinations thereof. 
     As previously described, pile segments  10  are vertically aligned and stacked to form pile  111 . In particular, pile segments  10  are stacked with each of their throughbores  40  substantially aligned. Further, throughbore  113  of cap  112  is also aligned with bores  40 , thereby forming a continuous passage  130  through cap  112  and pile  111  having an upper opening  130   a  in cap  112  and a lower opening  130   b  in the lowermost pile segment  10 . 
     In this embodiment, underpinning  100  also includes an elongate rod  125  disposed within passage  130 . In particular, rod  125  extends substantially through cap  112  and each pile segment  10  from proximal upper opening  130   a  to proximal lower opening  130   b  of passage  130 . Rod  125  may be solid or a tubular. In this embodiment, rod  125  is a tubular having an upper or first opening  125   a  in fluid communication with a lower or second opening  125   b . In either case, rod  125  is preferably rigid and is intended to provide structural support and reinforcement to underpinning  111 . Thus, rod  125  may also be referred to as a reinforcing rod  125  or reinforcing tubular  125 . Rod  125  may be constructed as pile  111  is built, or disposed in passage  130  following completion of pile  111 . 
     Referring still to  FIG. 4 , in this embodiment, reinforcing rod  125  comprises a plurality of elongate rod segments  126  coupled together end-to-end. It is to be understood that rod segments  126  may be solid or tubular, depending on whether it is desired that reinforcing rod  125  be solid or tubular. Adjacent rod segments  126  may be coupled end-to-end by any suitable means including, without limitation, mating threads, a mating collar and nut, welding, or combinations thereof. Regardless of the manner of coupling adjacent rod segments  126 , the coupling or connection between adjacent rod segments  126  preferably fits within passage  130 , thereby allowing reinforcing rod  125  to be disposed within passage  130  while allowing adjacent pile segments  10  to substantially engage each other end-to-end. For example, if throughbores  40  in each pile segment  10 , and hence, passage  130  of pile  111 , have a ⅝″ diameter, rod segments  126  and the coupling or connecting means between adjacent rod segments  126  preferably have a diameter less than ⅝″, for instance a ½″ diameter. Further, in some embodiments, a nozzle may be coupled to the second opening  125   b  of reinforcing rod  125  such that fluid entering first opening  125   a  of reinforcing rod  125  exits reinforcing rod  125  through the nozzle. 
     Reinforcing rod  125  is intended to promote the vertical alignment of pile segments  10  during construction of pile  111 , and serve to maintain the vertical alignment of pile segments  10  after completion of pile  111  by restricting lateral shifting or movement of pile segments  10  in pile  111  relative to each other. In this sense, inclusion of reinforcing rod  125  offers the potential to improve the overall stability and support capabilities of pile  111  and underpinning  100 . In general, reinforcing rod  125  may comprise any suitable material including, without limitation metals (e.g., copper), metal alloys (e.g., steel), non-metals (e.g., polymer, PVC, etc.), or combinations thereof. However, to promote and maintain vertical alignment of pile  111 , reinforcing rod  125  preferably comprises a relatively rigid material capable of resisting the lateral shifting of pile segments  10  relative to each other. For instance, rod segments  126  may comprise galvanized pipe. 
     Referring still to  FIG. 4 , in this embodiment, foundation underpinning  100  is supported by surrounding soil  70  and a support base  135 . As will be described in more detail below, support base  135  is preferably a substantially rigid mass formed by injecting a flowable material (i.e., base material) into the voids and spaces beneath pile  111 , and allowing the flowable material to solidify. Examples of suitable base materials include, without limitation, concrete, grout, polyurethane, and other materials that can be flowed beneath pile  111  and then allowed to solidify, thereby forming support base  135 . Once the material forming support base  135  solidifies and hardens, support base  135  restricts pile  111  and underpinning  100  from further settling into the soil over time. Support base  135  may be formed before or after pile  111  is completed. 
     The material forming support base  135  may be injected beneath pile  111  in any suitable manner. For instance, in embodiments having no reinforcing rod or tubular, the base material may be directly flowed through passage  130  or injected through a flexible tubular (not shown) disposed within passage  130 . In embodiments including a solid reinforcing rod, the base material may be flowed through the annulus formed between passage  130  and the reinforcing rod. Still further, in embodiments including a tubular reinforcing rod, the base material may be flowed through the reinforcing tubular. 
     It should be appreciated that after pile  111  is driven into the soil  70  and underpinning  100  is positioned to support structure  105  and its foundation  110 , the surrounding soil  70  will tend to settle and fill any spaces or voids adjacent side surfaces  21 ,  31  of each pile segment  10 . As the surrounding soil settles into these spaces, it will provide additional lateral support to pile  111  and underpinning  100 . Moreover, lower annular axial surface  32  of each pile segment  10  provides bearing surface area to level and/or support structure  105  and its foundation  110 . 
     Referring now to  FIGS. 5 and 6 , a representative method  200  to construct a pile (e.g., pile  111 ) is illustrated. For purposes of further explanation, pile segments  10  used to build pile  111  shown in  FIG. 6  are assigned reference numerals  10 - 1 ,  10 - 2 ,  10 - 3 , and  10 - 4 , there being four representative pile segments illustrated in  FIG. 6 . Pile segment  10 - 1  is the bottom or lowermost pile segment  10 , followed by pile segment  10 - 2 , and so on. 
     Method  200  begins with step  201  where a hole  300  is dug at least partially beneath a structure  105  and its foundation  110 . Proceeding to step  205 , a first pile segment  10 - 1 , substantially the same as pile segment  10  previously described, is positioned on the surface of the soil  70  at the bottom of hole  300 . In particular, first pile segment  10 - 1  is vertically oriented with its trunk  28 - 1  contacting the surface of soil  70 . First pile segment  10 - 1  is the first of a plurality of pile segments  10  that will be driven into the soil  70  to form pile  111  and underpinning (e.g., underpinning  100 ) such as those shown in  FIG. 4 . 
     With the first pile segment  10 - 1  properly positioned and oriented, a first reinforcing tubular segment  126 - 1  is inserted into bore  40 - 1  of first pile segment  10 - 1  and partially into the soil  70  according to step  210 . It is to be understood that at this point, reinforcing tubular  125  comprises only first reinforcing tubular segment  126 - 1 , and thus, the upper end of first reinforcing tubular segment  126 - 1  represents the first opening  125   a  of reinforcing tubular  125  while the lower end of first reinforcing tubular segment  126 - 1  represents second opening  125   b  of reinforcing tubular  125 . 
     Proceeding to step  215 , a jetting tube  350  is inserted through first reinforcing tubular segment  126 - 1 . Jetting tube  350  has an outlet end  350   a  and an inlet end  350   b  in fluid communication with outlet end  350   a . Outlet end  350   a  of jetting tube  350  is preferably advanced through first reinforcing tubular segment  126 - 1  until outlet end  350   a  reaches, or extends slightly from, the lower end of first reinforcing tubular segment  126 - 1  (i.e., second opening  125   b ). Jetting tube  350  is preferably a flexible tube made of a polymer or rubber material. 
     Proceeding to step  220 , inlet end  350   b  of jetting tube  350  is connected to a fluid jetting system (not shown). In some embodiments, prior to connecting inlet end  350   b  to the fluid jetting system, jetting tube  350  may be threaded through a plurality of unconnected reinforcing tubular segments (e.g., reinforcing tubular segment  126 - 4 ) and/or threaded through a plurality of individual pile segments (e.g., pile segment  10 - 4 ). In some cases, the reinforcing tubular segments and pile segments may be threaded in an alternating fashion. 
     Once outlet end  350   a  is sufficiently positioned and inlet end  350   b  is coupled to the fluid jetting system, a jetting fluid, such as water or the like, is pumped by the fluid jetting system through flexible tubular  350 . Specifically, the jetting fluid flows into inlet end  350   b , through jetting tube  350 , and out of outlet end  350   a . The jetting fluid moistens and loosens the soil  70  beneath first pile segment  10 - 1  and pile  111 . Moistening and loosening the soil  70  in this manner offers the potential to soften and reduce the resistance of the soil  70  to driving of pile segments  10  and pile  111  into the soil  70 . Consequently, the jetting process is intended to improve the ease and speed, as well as depth, that a jack or ran  325  can drive pile segments  10  and pile  111 . 
     Proceeding now to step  225 , a jack or ram  325  is positioned between foundation  110  and first pile segment  10 - 1 . Jack  325  may comprise any suitable device capable of applying a vertical force  80  sufficient to drive first pile segment  10 - 1  and pile  111  into the soil  70  including, without limitation a mechanical jack, a hydraulic jack, or the like. Jack  325  is preferably positioned to engage substantially the center of upper surface  33  of head  30  of the uppermost pile segment  10  to enable controlled, uniform vertical displacement of pile segment  10  into the soil  70 . In some embodiments, a spacer block  320  is positioned atop of the pile segment between the pile segment and jack  325 . Spacer block  320  is intended to enhance uniform distribution of vertical forces  80  across upper surface  33 . Such a spacer block  320  preferably includes a counterbore or recess  321  in its lower surface adapted to receive the upper end of uppermost reinforcing tubular segment  126 - 1 . In this manner, axial forces may be applied uniformly to upper surface  33  without crushing or damaging the upper end of the uppermost reinforcing tubular segment  126 - 1 . In addition, to enable continuous jetting while driving, spacer block  320  also preferably includes a radial through passage or groove in fluid communication with the counterbore  321 . Jetting tube  350  is positioned through such a passage or groove, through the counterbore  321  and into reinforcing tubular segment  126 - 1 . In this manner, jetting fluid may continue uninterrupted through spacer block  320  as pile segment  10 - 1  (as well as subsequent pile segments) is driven by jack  325 . In general, spacer block  320  may comprise any suitable material or shape; but preferably comprises an aluminum rectangular block. 
     With jack  325  sufficiently positioned, jack  325  is extended to push upward in the direction of arrow  18  on foundation  110  and downward in the direction  16  on first pile segment  10 - 1 . In other words, using slab  110  as leverage, jack  325  is actuated to drive first pile segment  10 - 1 , and any subsequent pile segments in pile  111 , downward according to step  230 . As previously described, moistening and loosening the soil  70  by the jetting process both prior to and during the driving of first pile segment  10 - 1  and pile  111  into the soil  70  offers the potential to soften the soil  70  and improve the ease and speed, as well as depth, that jack  325  can drive first pile segment  10 - 1  and pile  111 . In addition, moistening of the soil  70  with the jetting fluid tends to create lubricating effect, thereby reducing frictional forces between first pile segments  10  and the surrounding soil  70 . 
     Proceeding to step  235 , if first pile segment  10 - 1  and pile  111  have reached a sufficient depth to support, stabilize, and/or level structure  105  and foundation  110 , then fluid jetting may be terminated according to step  240 . In such a case, pile construction process  200  is complete and the remainder of the underpinning (e.g., underpinning  100 ) may be finished according to the underpinning completion process described in more detail below. However, if first pile segment  10 - 1  and pile  111  have not reached a sufficient depth, then a subsequent pile segment  10  and tubular segment  126 - 2 , such as a second pile segment  10 - 2  and a second tubular segment  126 - 2 , must be added to pile  111  and reinforcing tubular  125 . Specifically, jack  325  and spacer block  320  are removed from on top of the pile  111  according to step  245 . Then proceeding to step  255 , second tubular segment  126 - 2  is slid downward into position and coupled to the first tubular segment  126 - 1  already in place, and second pile segment  10 - 2  is placed atop, and vertically aligned with, first pile segment  10 - 1  according. 
     It should be appreciated that by pre-threading tubular segments and pile segments along jetting tube  350  as described above, the fluid jetting process need not be repeatedly interrupted to when additional tubular segments and/or pile segments need to be installed. In other words, with a sufficient number of tubular segments and pile segments threaded on jetting tube  350 , the jetting process need not be stopped and inlet end  350   b  disconnected from the jetting system in order to install additional tubular segments  126  and/or pile segments  10 . Alternatively, in embodiments where inlet end  350   b  of jetting tube  350  is connected to the fluid jetting system without first inserting it through additional rod segments and pile segments, fluid jetting may need to be interrupted to disconnect inlet end  350   b  from the fluid jetting system and to install additional rod segment(s) and/or pile segment(s). After adding the next rod segment and pile segment to the pile, inlet end  350   b  may be reconnected to the fluid jetting system and the jetting process continued. 
     Proceeding again to step  225 , jack  325 , and optionally spacer block  320 , are repositioned and utilized to drive second pile segment  10 - 2  and pile  111  (now comprising first pile segment  10 - 1  and second pile segment  10 - 2 ) into the soil  70  as previously described with respect to step  225 . Fluid jetting is preferably continued as second pile segment  10 - 2  and pile  111  is driven into the ground by jack  325 . This process of removing jack  325  and spacer block  320 , adding another pile segment to pile  111 , adding another reinforcing tubular segment to reinforcing tubular  125 , repositioning jack  325  and spacer block  320  between foundation  110  and pile  111 , and driving pile  111  into the soil  70  is repeated until pile  111  achieves a sufficient depth. Once pile  111  has reached a sufficient depth and fluid jetting has been terminated according to step  240 , jack  325  and spacer block  320  may be removed from pile  111 , the remainder of the underpinning (e.g., the underpinning base, cap, spacers, etc.) is completed according to the underpinning completion process  400  illustrated in  FIG. 7 . 
     Referring now to  FIGS. 4 ,  6 , and  7 , once pile  111  is driven to a sufficient depth, the remainder of underpinning  100  (e.g., support base  135 , cap  112 , spacers  115 , etc.) ( FIG. 4 ) may be constructed according to an underpinning completion process  400  ( FIG. 7 ). Starting with step  405 , jack  325  is removed from between the top of pile  111  and slab  110 , and further, jetting tube  350  is removed from reinforcing tubular  125 . Next, cap  112  is positioned on top of pile  111  according to step  415 . As best seen in  FIG. 4 , cap  112  is preferably positioned such that bore  113  of cap  112  is aligned with passage  130  of pile  111 . In such an orientation, first end  125   a  of reinforcing tubular  125  is permitted to slid into bore  113  without damaging or bending first end  125   a . Reinforcing tubular  125  is preferably long enough to extend completely throughbore  113  such that first end  125   a  extends beyond cap  113 . In the ease reinforcing tubular does not extend completely throughbore  113 , one or more additional reinforcing tubular segments  126  may be coupled to reinforcing tubular  125 , thereby increasing its length. 
     Referring specifically to  FIGS. 4 and 7 , proceeding to step  420 , spacers  115  are then positioned between cap  112  and slab  110 . If necessary, one or more shims  155  may be inserted between spacers  115  and slab  110  to ensure a tight fit between spacers  115  and slab  110  such that pile  111  will be restricted from substantial lateral movement. 
     Proceeding to step  425 , a base material injection system (not shown) is connected to first end  125   a  of reinforcing tubular  125 . The material forming support base  135  is then injected in a flowable state (e.g., liquid, wet slurry, etc.) into first end  125   a , through reinforcing tubular  125 , and out of second end  125   b . The flowable base material is intended to fill any spaces and voids in the soil proximal the bottom of pile  111 . The base material preferably hardens over time into a solid mass, thereby forming support base  135 . For instance, the base material may comprise a concrete slurry, grout, or polyurethane is flowed under pressure through reinforcing rod  125  and deposited under pile  111 . As stated previously, support base  135  supports pile  111  and restricts vertical pile  111  from further settling into the soil. 
     Reinforcing tubular  125  may also be filled with the base material. Without being limited by this or any particular theory, as the base material solidifies within reinforcing tubular  125 , it increases the rigidity and strength of reinforcing tubular  125 , thereby enhancing the ability of reinforcing tubular  125  to resist lateral misalignment of pile segments  10  in pile  111  that may otherwise occur from the shifting, swelling, and/or shrinking of the surrounding soil  70 . 
     Proceeding now to step  435 , after the support base  135  is formed and reinforcing rod  125  is filled with the base material, the base injection system is disconnected from first end  125   a  of reinforcing tubular  125 . At this point, foundation underpinning  100  is substantially complete and hole  300  may be refilled. 
     While various embodiments of a foundation underpinning and its methods of installation have been shown and described herein, modifications may be made by one skilled in the art without departing from the spirit and the teachings herein. The embodiments described are representative only, and are not intended to be limiting. Many variations, combinations, and modifications of the applications disclosed herein are possible and are within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is defined by the claims which follow, that scope including all equivalents of the subject matter of the claims.