Abstract:
An excavation wall retaining assembly for use during repairs of damaged, earth ground-embedded fluid pipes, comprising: a first series of lowermost walls, vertically installed at the periphery of the lower section of an excavation made in the ground about the fluid pipes; feet releasably supporting the first series of walls spacedly above the flooring defined by the excavation; at least a second series of upper walls, vertically installed edgewisely over the first series of walls, supportingly by the latter. Jacks provide releasable, adjustable, compressive biasing forces against the walls so as to retain the latter in vertical position against caving in of surrounding earth. The wall retaining assembly is dismantleable and all of its structural elements are fully retrievable after use, from the bottom up or from top to bottom.

Description:
FIELD OF THE INVENTION 
     This invention relates to wall assemblies to temporarily maintain the shape of a ground trench, ditch or the like excavation into which workers are to work, e.g. to repair damaged ground utility pipes passing therethrough. 
     BACKGROUND OF THE INVENTION 
     U.S. Pat. No. 4,019,328 to Jean Marie Gerard Koehl, shows that it is known to use cross-sectionally I or H-shape beams as the structural frame of a wall support assembly for excavations such as trenches or ditches. It is also known to use wooden planks retainingly slidingly engaged into the U-shape channels of the I-beams frame, to retain the earth wall of the excavation: see U.S. Pat. No. 841,773 to Albert Fitzgerald. This latter patent also shows adjustable, elongated jack members extending transversely through an excavation, for applying compressing forces against a wall support assembly in an excavation, to bias the latter outwardly against the earth wall to prevent caving in. Fitzgerald also shows enlarged support plates at the ends of the jack members. 
     However, a major disadvantage of the known wall support assemblies is that the structural elements thereof usually have to be left in place in the excavation after use: they are unretrievable. This means that the whole capital cost of the wall support assembly is added to the workers&#39; time in the computation of the overall cost for repairs in the excavation--a wasteful inefficiency. Moreover, it requires know-how to install in a proper way the wall support assemblies, while preventing any hazard to the workers installing the wall assembly, e.g. landslide while the workers are located into the excavation. 
     OBJECTS OF THE INVENTION 
     The main object of the invention is thus to provide a wall support assembly for ground excavations including trenches, ditches and the like, which will be very easy to install or dismantle. 
     A further object of the invention is to provide such a wall support assembly, which will enable the retrieving of all structural elements after use, for substantially increased cost-effectiveness. 
     SUMMARY OF THE INVENTION 
     Accordingly with the objects of the invention, there is disclosed an excavation wall retaining assembly for use during repairs of damaged, earth ground-embedded fluid pipes, said wall retaining assembly comprising: (a) a first series of lowermost wall members, vertically installed at the periphery of the lower section of an excavation made in the ground about said fluid pipes; (b) base members, releasably supporting said first series of wall members spacedly above the flooring defined by said excavation; (c) at least a second series of upper wall members, vertically installed edgewisely over said first series of wall members, supportingly by the latter; wherein some sections of said first or second wall members have apertures for through passage of said fluid pipes transversely of said excavation; (d) securing means, releasably anchoring said lowermost wall members edgewisely to said second series of wall members; and (e) biasing means, providing releasable, adjustable, compressive biasing force against said wall members so as to retain the latter in vertical position against caving in of surrounding ground earth; wherein said wall retaining assembly is dismanteable and all of its structural elements are fully retrievable after use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top plan view of a road pavement, showing in phantom lines a network of ground-embedded fluid pipes; 
     FIG. 2 is a vertical sectional view of the ground, taken along line 2--2 of FIG. 1; 
     FIG. 2a is a view similar to that of FIG. 2, but with an excavation having been dug along the broken lines 2a--2a of FIG. 1, and further illustrating a partly broken excavation wall retaining and scaffolding system according to the invention; 
     FIG. 3 is a partly broken, enlarged view of the area circumscribed by arrow 3 in FIG. 2a; 
     FIGS. 4-6 are enlarged view of the areas circumscribed by arrows 4-6 respectively of FIG. 2a; 
     FIG. 7, on the third sheet of drawings, is a view about perspective 7 of FIG. 4; 
     FIG. 8 is an extended view at a smaller scale of FIG. 5, showing in dotted lines how the bottom I-shape excavation support truss can be pivotally removed from the excavation; 
     FIGS. 9-10 are cross-sectional views along lines 9--9 and 10--10 respectively of FIG. 6; 
     FIG. 11 is a top plan view of a corner portion of the excavation and associated supporting wall assembly, at an enlarged view relative to FIG. 2a; 
     FIG. 12 is a side elevational view of the elements of FIG. 11; 
     FIG. 13 is an isolated view of one wall frame element of FIG. 10; 
     FIGS. 14-15 are front and side elevational views respectively of the wall frame element of FIG. 13; 
     FIG. 16 is a cross-sectional view taken along lines 16--16 of FIG. 15; and 
     FIG. 17 is an enlarged perspective view of the supporting foot from the wall retaining system, also illustrated at the bottom of FIGS. 5 and 8. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As can be seen in FIGS. 1-2, a network of utility pipes P 1 , P 2 , conventionally extend in a modern city horizontally through ground or earth E, below asphalt pavement A and its supporting gravel layer G. These pipes may carry for example water W. Elbowed portions of the pipes P 1 , P 2 , are prone to break or be damaged more often than the straight portions thereof, and thus, means must be devised to reach these areas in the ground and to enable a worker to effect the repairs. This is done by digging through pavement A, gravel G and earth E, in register with one or more broken pipe sections P 3 , so as to define an excavated area 20 which may be for example of cubic shape. Hence, pipe section P 3  extends freely horizontally through excavation 20, being endwisely anchoringly embedded into the earth E. Excavation 20 defines a floor 22, four side walls 24, and a top mouth 26 coplanar to asphalt A. 
     To maintain the cubic shape of the excavation 20, a supporting wall assembly 28 needs to be installed, at least for the time required by the workers to effect the repairs to the damaged pipe section P 3 . Wall assembly 28 includes a series of spaced, vertically extending, rigid beams or post sections 30, of I shape in cross-section and aligned in end-to-end relation. I-beams or post sections 30 are applied spacedly against each of the four walls or faces 24 of excavation 20, as illustrated in FIG. 2a, wherein a pair of opposite channels 30a of U-shape cross-section are defined for each postsection 30 (FIG. 10). Each portion 30 has a web 30b, an outer flange 30c, and an inner flange 30d. Outer flange 30c is applied flat against excavation face 24. A number of sheeting planks 32 of same length extend horizontally between each successive pair of post sections 30 on a same excavation wall 24, in superimposed fashion, so as to endwisely engage into the channels 30a of these two supporting post sections. Accordingly, a wall of horizontal planks 32 is defined. Obviously, openings 34 will be made through some sections of planks 32&#39;, to allow through-passage of the damaged pipes P 3  to be repaired for access by the workers in the excavation 20. 
     In each corner of the wall of planks 32, as shown in FIGS. 11-12, a modified beam 30&#39; is provided, wherein its two U-shape channels 30a&#39; are at right angle to each other rather than at 180° as with I-beam 30. Such a beam 30&#39; could be as illustrated in FIG. 11, being of generally+shape in cross-section and further including an integral outer truss panel 36 bent at right angle in three straight segments in 45° increments, panel 36 joining the two U-shape channels 30a&#39;. 
     Vertical beams 30 on opposite walls 24 should be in respective registering pairs. To prevent the earth wall 24 and thus wooden planks 32 from caving in with time and filling excavation 20, elongated jack members 38 are required to each spacedly engage against a pair of opposite beams 30, in horizontal position above the floor 22 of the excavation 20. One jack member 38 is shown in broken view in FIG. 3. Jack member 38 includes a threaded rod 40, threadedly axially engaged into the inwardly-threaded end 42a of an elongated tubular casing 42. The diametrically enlarged untreaded outer end section 40a of rod 40 is partly freely engaged into a rigid cross-sectionally quadrangular socket 44, which is anchored to and protrudes from the top end of each 30. From the end of each rod end section 40a protrudes a diametrally smaller cylindrical extension 46 having a conical tip 46a. Rod extension 46 extends through a rigid annular ring 48, which is anchored into the first socket 44 in substantially coaxial fashion therewith. Rod extension 46 extends short of the base wall 44c of the socket 44. The annular seat 40b formed by the free end of rod end section 40a radially outwardly from extension 46, comes to abut against the annular free edge 48a of inner ring 48. Extension 46 is shorter than the length of inner ring 48, so that its conical tip 46a will clear the base wall 44c of socket 44, opposite its free outer edge 44d, as clearly illustrated in FIG. 3. A handle lever 50 extends transversely through rod section 40a outwardly from socket 44, and is anchored welding D to rod section 40a at its intermediate section. 
     Rotation of lever 50, will reciprocate rod 40 through casing 42. 
     As illustrated in FIGS. 10 and 16, the opposite end of tubular casing 42 includes a diametrally smaller, cross-sectionally quadrangular extension 43 partially engaging quadrangular socket 44&#39; anchored to an I-beam 30 on the opposite side of the threaded rod 40 of that jack member 38. Socket 44&#39; and the inner ring 48&#39; are similar to socket 44 and ring 48, respectively, so that the jack members can be reversed from end to end. Square socket 44 or 44&#39;, when receiving extension 43, prevents rotation of jack 38 about its longitudinal axis. 
     Hence, through forcible manual rotation of handle 50, rod 40 can be outwardly extended to put horizontal biasing pressure against I-beams 30, wherein the associated wooden plank wall 32 will be biased flatly vertically against the side wall 24 of earth E making the side walls of the excavation. At least a few such jack members are installed for each of the two pairs of excavation walls 24, as suggested in FIG. 2a. 
     Against the inner flange 30d of two adjacent I-beams 30 can be releasably anchored a transverse reinforcing I-beam 54 by a bolt-and-nut assembly 56, the bolt being welded to the beam flange 30d, (FIG. 3). I-beam 54 is used adjacent piping P1, P2, or P3, whenever such piping prevents installation of jacks 38. A pair of oppositely-directed short cylindrical studs 58a are secured as by welding D to the opposite sides of each quadrangular socket 44. A tube 58 can be fitted over and supported at its ends by studs 58a of two adjacent beams 30. Tube 58 extends spacedly proximate and parallel to planks 32. Tube 58 can support by arcuate rigid arms 60 a horizontally-extending work-platform 62 (FIGS. 6, 9, and 10). Obviously, arms 60 are secured to and project from each end of platform 62 and hook onto a corresponding tube 58. 
     Platforms 62 constitute a scaffolding assembly, which is to be used above floor 22 to allow the workers to work directly in front and at the level of the damaged pipe section P 3  to be repaired. 
     The heart of the invention lies in the detail shown in FIGS. 4, 5, 8, 12, 14 and 17. Each I-beam 30 includes two downwardly-dependent rigid tongues 64, fixed flat to both sides of the web 30b of beam 30 at the bottom end thereof. Indeed, a number of vertical I-beams 30 are endwisely vertically superimposed, as shown in FIGS. 4, 5, and 8 and secured to one another at their upper and lower ends by bolts or pins 72 extending through bores 64a of tongues 64 and bores 64b at the top ends of the web 30b of I-beams 30. Tongues 64 straddle the web of the adjacent beam 30. The pair of tongues 64 maintain the webs 30b of two adjacent beams 30 in alignment, while the flanges 30c, 30d of the same beam are kept in alignment by the outer edges 64c of tongues 64, which overlap the top end of the outer flange 30c of the lower beam 30&#34;, and by the socket 44, which forms a block protruding upwardly from the top end of the inner flange 30d of the adjacent lower beam 30&#34; and which overlaps the inner flange 30d of the adjacent upper beam 30 (FIG. 4). Jacks 38 are applied at the junction of two beams 30 or 30, 30&#34;; therefore, usually no additional jacks or braces are required to brace the post sections or beams 30 except for the opposite lowermost beams where a brace 38 should be applied against a nipple 44a fixed to the lower end of the beams 30 (FIGS. 5 and 2a). The uppermost or lowermost I-beams 30 could be removed by upward or downward pulling, respectively, and so on until all the I-beams are removed. Foot members 66 [FIGS. 5, 17] are first positioned on flooring 22 and connected by bolts 72 to the tongues 64 of the lower series of I-beams, to endwisely support vertical I-beam 30&#34; spacedly above ground 22. 
     Each foot member 66 defines a large base plate 68 and a transverse arm 70. Upwardly projecting arm 70 and tongue 64 each includes an endwise through bore 70a, 64a releasably engaged by a bolt and nut assembly 72 to anchor the arm and tongue together. Base plate 68 has a transverse bore 74 for releasable engagement by a ground peg 76 for temporarily anchoring foot member 66 into the ground 22, directly in vertical register under tongue 64 of the lower series of I-beams 30&#34;. 
     The method of installation of the supporting wall assembly 28 is as follows. After the excavation 20 has been dug, the feet 66 and lowermost I-beams 30&#34; are installed in upstanding position onto floor 22. The wooden planks 32 are then horizontally positioned to laterally support earth walls 24, by endwisely slidingly engaging the top mouth of the vertical channels 30a of I-beams 30&#34;, and are stacked until the entire height (or length) of the I-beams 30&#34; is occupied by the wooden planks 32. The lowermost plank 32 will not fall under I-beams 30&#34; (laterally of feet 66), since the tongues 64, which are welded at D to I-beams 30, 30&#34;, have substantial thickness and will each act as a seat to retain the lower plank of that level series of wall member planks and I-beams. 
     Upper adjacent I-beam endwise sections 30 are each vertically positioned endwisely over a corresponding lower I-beam 30&#34;, its end tongues 64 being releasably anchored to the top of I-beam 30&#34; by a bolt/nut assembly 72. Again, wooden planks 32 are horizontally engaged into the top mouth of this second level of I-beams 30, to slide downwardly by their own weight along the vertical U-channels 30a, down to the corresponding tongues 64 which will stop them, as explained hereinabove for the lowermost I-beams 30&#34;. The planks 32 will therefore become stacked spacedly over the planks retained by I-beams 30&#34;. This is repeated a number of times until pavement level A is reached. If so desired, the length of planks 32 can be shortened to clear tongues 64 and thus eliminate any gap between the planks 32, as shown in FIG. 2A. 
     I-beams 30, 30&#39;, 30&#34; may be of a suitable materiel in various standard lengths. 
     The elongated jacks 38 are then horizontally installed to retain the beams 30, 30&#34; in position, the strong pressure exerted by the jacks against the walls 32 will anchor the latter to the earth wall 24; thus, when the platforms 62 will be installed to the walls 32 and workers and equipment will weight on the whole assembly 28, it is understood that the feet 66 will be substantially relieved from sustaining this weight load, due to the major contribution of the overlying jacks 38 which extend transversely of the excavation 20. 
     When repairs to the damaged pipes P 3  at the lowermost area of the excavation 20 are completed, the corresponding jack members 38 are first unscrewed and removed; thereafter, feet 66 are removed by pulling out the pegs 76, disconnecting bolts 72, sliding plates 68 away from wall 24 to clear the area under the I-beam 30&#34;. The lower I-beams 30&#34; will fall by their own weight at least until their bottom, downwardly projecting tongues 64 abut the ground 22; this necessarily should clear the tongues 64 of the next adjacent upper series of I-beams 30 from the top edge section of the lower level series of I-beams 30&#34;, wherein the latter I-beams 30&#34; may then be pivotally removed from wall 24 as suggested in phantom lines in FIG. 8. The wooden planks 32 from the upper I-beams 30 will not fall down because of the tongues 64, but will remain within the U-channels of the second level series of I-beams 30. The planks 32 are released from the I-beams 30&#34;&#39;. 
     Hence, every structural element of the lower section of the support wall assembly 28 is retrieved: there is nothing left behind. There is thus no waste, allowing full recovery of capital cost. 
     Wall assembly is preferably removable from the bottom up to permit gradual earth-billing of the excavation but it is also possible to dismantle same from top to bottom, although this is less safe because of possible landslides--a hazard to the safety of the workers still in the excavation.