GB2053314A - Trench shoring - Google Patents

Abstract

Trench shoring includes guide rails, 1a, 1b, 2a, 2b, employed in two pairs as a unit, along which wall panels 6a, 6b are guided and supported. Between each pair of guide rails disposed on opposite sides of a trench, struts 4 are pivotally connected, and at least two safety ropes 5a, 5b, which extend loosely diagonally in opposite directions. Also disclosed is a device for pulling out the panels upon completion of back filling of the trench with soil, and a device 15 for connecting upper and lower panels 6a, 6b together. <IMAGE>

Description

SPECIFICATION Soil-retaining wall structure.

The present invention relates to a soil-retaining wall structure to be utilized in various civil engineering works such as ground excavation works for example.

For an underground installation of concrete pipes for water supply systems, city sewer systems and so on, cables for power supply, telecommunication systems and the like, box culverts, and so forth, required are ground digging works, in which required in turn is to provide by digging a channel, trench or the like of a minimum width required for such underground installation.

It often tends to occur during ground excavation works that side walls of a trench or the like under digging will suddenly undergo collapsing particularly when the trench is of a relatively small width or of a relatively great depth.

To avoid occurrence of such accident, it has been conventionally practised to form the excavation wider than necessary or raise a number of piles along the sides of the excavation being formed and plant steel panels or wood plates between the side wall surface of the excavation and piles. It also is known to apply sheet piles in two continuous rows along the sides of the trench and operate ditching between such rows of sheet piles.

With the above conventional means for retention of soil along sides of an excavation such as a trench complex is the operation for driving into the ground such as piles and/or steel sheet piles, which requires not only a particular driving machine but also a high degree of skill, and it often results in that the time consumed for the soil retention work exceeds the time required for the excavation operation itself.

Further, although in recent years the trench excavation is worked more often than before with use of a power driven excavator such as for example back-hoes, in such cases again whether or not the ditching operation can be efficiently worked and whether ditching of a minimum width trench or channel can be successfully made are greatly influenced by the particular means employed for the prevention of ground collapsing.

Accordingly, a primary object of the present invention is to provide a soil-retaining wall structure or assembly, with which various shortcomings as indicated above in connection with the conventional means for the prevention of collapsing of side wall grounds of a trench or the like to be excavated can be effectively cancelled.

it lies within objects of the present invention to provide a soil-retaining temporary wall assembly, with which operable with ease are the assemblage of and decomposition to component members and also an adjustment of the distance between a pair of wall panels parallel disposed along sides of the trench or the like.

It also is within objects of the present invention to provide a soil-retaining temporary wall structure, with which increasingly additional wall panels can be assembled as the excavation is formed to a greater depth and/or length, and upon completion of installation of for example a pipeline relative to the bed of the trench and back filling of the trench with soil, the structure can be easily pulled out of the ground and decomposed to its component members.

To reduce those and other inventive objects to practice, the temporary wall structure embodying the concept of the present invention is essentially characterized in that it includes as a structural unit or set two pairs of guide rails raised in an arrangement such that one and the other of two guide rails of each pair are respectively disposed at one and the other sides of an excavation such as a channel, trench or the like to be ditched, rail connecting struts pivotally applied between such pair of guide rails, at least two safety rope members loosely extended across the pair of rails in a manner of being loosely extended across the pair of rails in a manner of being inclined in opposite directions, and wall panels placed and received by fitting between two guide rails located adjacent to each other in the direction in which the excavation is formed increasingly to a greater length.The device for removing by pulling the wall structure or, more particularly, the wall panel members once built into the ground, which the present invention also proposes for use, utilizes a jack for facilitating pulling out of the wall panel by a crane.

The foregoing objects, structural characteristics and advantages of the present invention will become more fully apparent as the following description is considered in conjunction with the accompanying drawings, in which: Figure 1 is a partly exploded perspective view, showing the assemblage of component members of the soil-retaining temporary wall structure according to the present invention; Figure 2 is a front elevational view of a wall panel member of the structure of Fig. 1 with a portion thereof exploded for illustration of the interior structure of the panel member; Figure 3 shows a top plan view of the panel of Fig. 2; Figure 4 is a fragmentary front elevational view of a wall panel of a modified structure according to the present invention; Figures 5 and 6 are respectively a right side elevation and a top plan of the wall panel of Fig. 4;; Figure 7 is a partly cut-away side elevational view, showing the interior structure of a further modified wall panel according to the present invention; Figure 8 is a sectional front view, showing the detail of stopper members provided to vertical reinforcement members in the wall panel of Fig. 7; Figure 9 shows a side elevational view of a lower wall panel according to the present invention; Figures 10, 11 and 12 respectively show a front view, a top plan view and a side elevational view of a connecting member for lower and upper panel members according to the present invention; Figure 13 is a view taken for illustration of the manner of connecting together a lower and an upper wall panels; Figures 14 and 1 5 are respectively a front view and a side elevational view, showing an example of the guide rail of the present invention;; Figure 1 6 is a cross-sectional view of the guide rail of Figs. 14 and 1 5 and illustrates the manner of connecting laterally adjacent wall panels together through a guide rail; Figure 1 7 similarly is a cross-sectional view, showing a guide rail of a modified structure; Figure 18 is a front elevational view, showing a detailed arrangement of strut members and safety wire ropes applied between a pair of guide rails; Figure 19 is a front elevational view, illustrating the manner in which a pair of guide rails are supported relative to each other by upper and lower support; Figure 20 shows an enlarged view of the point at which the strut is connected to the guide rail; Figure 21 is a sectional view, illustrating the assemblage of component members of the strut;; Figure 22 shows an exploded view, taken for illustration of the component members of the strut; Figure 23 is a schematic front view, showing an instance of the application of the retaining wall structure of the present invention; Figure 24 is a front elevational view of a device for removing the wall panel of the structure of the present invention; and Figure 25 shows a side elevational view of the device of Fig. 24.

The present invention will now be described in detail in conjunction with the accompanying drawings illustrating specific embodiments thereof.

The soil-retaining temporary wall structure according to the present invention broadly comprises such an assembly as illustrated in Fig.

1, which includes guide rails as shown by reference characters 1 a, 1 b, 2a and 2b, each of which has a tapered lower end 3 for ease of their penetration into the ground when so driven.

Between the pair of guide rails 1 a and 2a which are parallel disposed with space along left and right sides of a trench or the like to be dug and that of rails 1 b and 2b, respectively, rail supporting struts 4 are disposed, supporting two guide rails of each pair relative to each other. The strut 4 is pivotally connected to the pair of guide rails in a manner such that two guide rails in a pair can be driven to move relative to each other in the longitudinal direction thereof; As the pair of guide rails are penetrated at different depths into the ground, the shape defined between the pair of rails and also the pair of upper and lower struts, which generally depicts a rectangle in an original arrangement of the rails and struts in a front view thereof alike the view in Fig. 18 for example, can undergo deformation but within the class of parallelograms.

Also applied between each of pairs of guide rails 1 a and 2a and 1 b and 2b are safety rope members 5a and 5b disposed in a manner of being slant in opposite directions or crossing with each other, which constitute an important member in the structure of the present invention and which are utilized in controlling the depth of penetration of respective guide rails into the ground as will later be described in greater detail. The rope member may comprise a wire rope for example, preferably including a chain connected at one or both longitudinal end or ends thereof as illustrated in Fig. 1 so that the length of the rope member can be more easily adjusted when so required.

Between guide rails 1 a and 1 b and also between rails 2a and 2b, respectively, there are disposed an upper wall panel 6a and a lower wall panel 6b, which are connected to guide rails at their side ends through their rail engaging portions. Similar to guide rails, the lower wall panel 6b has its lower end 7 tapered for increased ease of its penetration into ground.

Now, with the reference transferred to Figs. 2 and on, an explanation will next be entered in connection with various members constituting, in combination, the temporary retaining wall assembly according to the present invention.

Wall panels Initially in Figs. 2 and 3, which show an example of an upper wall panel 6a, the panel 6a as a whole comprises relatively thin box-like structure, of which the surface is composed of outer plates 8a and 8b made of a metal plate material, side plates 9a and 9b also made of metal plates and connected by welding to side ends of the outer plates, and upper and lower frames 1 Oa and 1 Ob made of a shape steel and connected by welding to the outer plates and side plates. Also, the panel 6a houses therein vertical and lateral reinforcement members or ribs indicated respectively at 11 and 12, which are structured in a lattice arrangement and to which the outer plates 8a and 8b are fixed by welding. In the illustrated example of the wall panel, the vertical rib 11 is made of a square or similar angle shape steel and the lateral rib 12, a channel steel.

However, it will be readily understood that the vertical rib 11 in particular may well comprise a pipe circular in cross section, in place of an angle shape steel pipe. Where a wider variety of crosssectional sizes are commercially obtainable of cylindrical pipes rather than angle shape pipes, it may rather be that the former is preferred to the latter. Also, a panel connecting member 1 5 as will later be described, which consists of a rod-like member round in cross section, is to be inserted into the hollow of the pipe rib 11, and a cylindrical pipe may be more advantageously utilized for the rib than an angle shape in that an overall face-toface contact can be realized between the inner surface of a cylindrical rib 11 and the outer peripheral surface of a rod-like connecting member 15, which is not realizable in the case of an angle shape pipe 11 receiving in its hollow a rod-like member 15.

The vertical reinforcement rib 11 has near its upper and lower ends stopper members 1 3a and 1 3b, which have an angled shape in cross-section and are provided to the rib by welding in a manner of protruding inwardly through a notched portion of the wall of the tubular rib. Further, at the lower edge portion at which the lower end of the vertical rib 11 is located, the upper wall panel 6a has a notched portion 14 opened toward inside of a trench or a like excavation being dug: In other words, the lower frame 1 Ob is formed with a cavity at such notched portion 14. This notched portion 14 provides an access for the operation of a spanner for rotating the panel connecting member 1 5 to be inserted into the hollow of the vertical pipe rib 11.

In this connection, although in Fig. 1 the notched portion 14 mentioned is illustrated as being opened toward outside of the rail and panel assembly, this is only for ease of illustration and, in actuality, the notched portion should preferably be formed on the inner surface of panels 6a in the illustrated assembly.

Figures 4, 5 and 6 altogether show a modified example of the upper panel 6a, and in the panel of this example, which greatly differs from the panel illustrated in Figs. 2 and 3 with respect to the rail engaging pqrtion, the side ends are notched as indicated at 16 to form a narrowed end portion, to which an outer side plate 9c is attached. At an upper end portion, the plate 9c has an outwardly protruded hook member 1 7. Further, vertically spaced along the side plate 9c, there are rollers 9d provided, which may normally be mounted in the number of two for each panel as illustrated, but the number of rollers can be suitably increased or decreased as needs be. Also, although they are dropped in the illustration of panels 6a in Figs. 2 and 3, the rollers 9d can also be secured to the side plates 9a and 9b of the panels of Figs. 2 and 3.

Then, in Figs. 7 and 8 there are illustrated, respectively, cross-sectional shapes of vertical and lateral ribs 11 and 12, and a detail of the manner of attachment of stopper members 1 3a and 1 3b to the rib 11. In the wall panel 6a under consideration, the lateral rib 12 comprises a channel steel.

Illustrated in Fig. 9 is an example of the lower wall panel 6b, of which the lower end is tapered as at 7, as before stated.

Connection of upper and lower panels As illustrated in Fig. 1, upper and lower wall panels 6a and 6b supported between guide rails 1 a and 1 b and also between rails 2a and 2b are connected together by panel connecting members 15, which have been inserted into ends of vertical ribs 11 of the panels 6a and 6b and rotated at 900, whereby their rib engaging portions are in engagement with the stoppers 1 3a and 1 3b of ribs.

Figures 10, 11 and 12 show detail views of the panel connecting member 15, which broadly comprises a round steel bar or rod provided with a neck portion 23 in the vicinity of each longitudinal end thereof forming the rib engaging portion 24, and a spanner engageable portion 25 longitudinally at a central portion thereof. As shown in Figs. 10 and 12 in particular, the rib engaging portion 24 is formed by reducing the thickness of the rod to a thickness or width b small enough to pass through the space between stoppers 1 3a and 13b. Also, as shown in Fig. 11, the panel connecting member 1 5 has a jaw J at its portion 24, which is swelled in comparison to its neck portion 23 and with which it can abuttingly engage the stoppers 1 3a and 1 3b of rib 11.

The connecting member 1 5 may be insertion applied into the vertical rib pipe 11 of the upper panel 6a and the corresponding pipe 11 of the lower panel 6b, and as shown in Fig. 13, a spanner 26 may then be applied to the member 15 through the notched portion 14 provided at the lower edge of the upper wall panel 6a. Then, the spanner 26 may be rotated as shown by an arrow in Fig. 13 to let the jaw J of the rib engaging portion 24 be engaged with stoppers 1 3a and 1 3b as stated above.

Guide rails Guide rails 1 a, 1 b, 2a and 2b for wall panels 6b shown in Figs. 2 and 3, which are shown in Figs.

14 to 16, individually have a cross-sectional particularity as illustrated in Fig. 1 6 and comprise an inner plate 18, outer plate 19 and their connecting member 20. In the space formed inner to the plates 1 8 and 1 9 and outer to the connecting member 20, a panel receiving portion 27 is formed into which the side end plate 9a or 9b of wall panels is vertically slidably received by fitting. The inner plate 18 is provided with joint pieces 21 for connecting struts 4 thereto and brackets 22 (Fig. 1 5) for connecting safety wire ropes 5a and 5b thereto.

The cross sectional view of Fig. 1 7 is of the guide rails shown in Fig. 1, and in this instance an inner plate 18' and outer plate 1 9' are welded to an H-shape steel, which is utilized as the connecting member 20' similar to the member 20 in the instance of Fig. 1 6. The reference numeral 27' shows the portion for therein receiving the side end 16 including side end plate 9c of the panel 6a in Figs. 1, 4 to 6 and also of the panel 6b in Fig. 1.

As illustrated in several figures of the accompanying drawings and as above described, guide rails 1 a, 1 b, 2a and 2b individually comprise a single rail structure. However, it may be readily understood that the guide rail can be so fabricated as to have a double rail structure comprising two rail members disposed longitudinally parallel with each other and integrally connected together or have a triple rail structure comprising three rail members integrally connected altogether like in the case of the double rail structure: When an intended excavation should exceed a depth of 7 to 8 m below the ground surface for example, advantageously employed may be guide rails of a double or triple rail structure as above, having an increased resistance against application of force such as soil pressure in comparison to a single rail structure.Further, in case of a double rail structure, a pair of lower and upper wall panels 6b and 6a be disposed in engagement with the inner rail member, and another pair of panels, along the outer rail member, whereby removal of panels by pulling-out can be effected with each pair of panels as a unit and can therefore be greatly facilitated in comparison to a case where for example four panels are connected altogether in a vertical series and are to be pulled out altogether at a same time. In case of a guide rail of the triple rail structure, a first, second and third pair of a lower panel and an upper panel may be placed in engagement with, respectively, the innermost, middle and outermost rail members.

The temporary wall structure having the foregoing structural features according to the present invention may be expediently assembled as follows: The front elevational view of Fig. 1 8 illustrates an aspect of the assembling of the retaining wail structure of the present invention, and as illustrated, struts 4 are pivotally secured through pins 33 to the joint pieces 21 integrally provided to the inner plate 18 of guide rails 1 a and 2a (and 1 b and 2b). Normally, struts 4 may be employed in a number of 2 to 3 for each parallel disposed pair of left and right guide rails 1 a and 2a or 1 b and 2b, but in practice the number of struts to be employed should be suitably determined taking into consideration the particularity of the nature of the ground or soil for excavation and the size of the overall wall structure required therefor.

As shown in greater detail in Figs. 19 and 22, the strut 4 is composed of a first end metal fixture 28, turnbuckle 29, coupling 30, supporter 31 and a second end metal fixture 32. The end portion of the metal fixtures 28 and 32 through which the pin 33 is applied is formed to have a cylindrical peripheral face so that it can contact the guide rail in a line-to-line manner of contact.

Preferably, supporters 31 of a variety of sizes or lengths should be prepared so as to accommodate for a variety of widths of trenches to be dug.

Abutting faces of various members of strut 4 recited above are compensationally tapered as indicated by Tin Figs. 21 and 22, and when a force becomes applied, pressing the metal fixtures 28 and 32 toward each other, adjacent tapered faces Tcan abut against each other to bring the various members of the strut in a condition closely bearing against one another, whereby the strut 4 can become a hardly deflexing integral body having a high strength standing against a relatively high soil pressure in case of collapsing of the trench wall.

Further, by rotating male and female screws 29 forming a member of the turnbuckle 29, it is feasible to suitably adjust the length of the strut 4 and accordingly the distance between the pair of guide rails 1 a and 2a or 1 b and 2b.

As before stated in brief, safety rope members 5a and 5b are connected preferably through chains to brackets 22 of rails 1 a and 2a (and 1 b and 2b) in a mutually crossing manner. When struts 4 are in a condition of being perpendicular to the pair of guide rails 1 a and 2a (1 b and 2b) as shown in Figs. 1 and 18, the ropes 5a and 5b are in a more or less loose condition of straining. Each rope has a length greater than the predetermined maximum distance between the pair of guide rails disposed at left and right sides of an excavation, and two operatively associated ropes may be applied in a manner of slanting in two opposing directions or, in practice, in a mutually crossing arrangement as above set forth.

Upon completion of assemblage of guide rails 1 a and 2a, struts 4 and safety ropes 5a and 5b in a condition as shown in Fig. 1 8, planting of the guide rail assembly may be operated.

In lifting the guide rail assembly with use of a crane, it may tend to occur that either of the two rails is lifted higher or lower than the other.

According to the present invention, however, safety wire ropes 5a and 5b are extended in a mutually crossing manner across the two rails, and in case of an unbalanced lifting of rails as above, either of the two ropes can undergo straining to effectively check any excessively unbalanced condition of lifting of rails.Also, in gradually settling the rails one by one into the ground, the degree of penetration of respective rails can be suitably controlled through visually observing the degree of tension of respective ropes: For example, in driving into the ground the guide rail 2a by pressing it at its head, the driving operation may be continued until the safety rope 5b is so strained as to take the phantom line position 5b' in Fig. 1 8 or a position close thereto, and then the other guide rail 1 a may be driven to penetrate into the ground with an attention by viewing paid at the changing degrees of straining of the other rope 5a.

With use of the retaining wall assembly of the present invention, excavation works may be efficiently operated through successive steps of: (1) Planting in the ground a first pair of guide rails 1 a and 2a; (2) slidably inserting a lower wall panel 6b into its receiving portion of each of rails 1 a and 1 b, (3) raising a second pair of guide rails 1 b and 2b, (4) digging, (5) penetrating panels 6b by pressing into the ground, (6) driving rails 1 a, 2a, 1 b and 2b deeper into the ground, (7) digging for the application of upper panels 6a, (8) applying panel connecting members 15 into ribs 11 of panels 6b, (9) inserting panels 6a along guide rails, (10) connecting together lower and upper panels 6a and 6b by the panel connecting members 1 5, and (11) raising a next pair of guide rails 1 c and 2c (not shown).

A difficulty likely to be involved during the above series of excavation steps (1) through (11) consists in the possibility that either of the operatively associated, parallel arranged pair of guide rails can be driven excessively deep into the ground than the other.

According to the present invention, however, the displacement in the height of such pair of guide rails can take place in a relative manner, and in case the amount of relative displacement of the two rails tends to become excessive, either of two safety wire ropes undergoes straining to effectively control the amount of the relative displacement, whereby the pair of guide rails can be driven into the ground in a baianced manner of penetration and the excavation works can be done with safety and accuracy as well.

Now, an explanation will next be made in relation to more practical steps for excavation works with use of the structure of the invention.

In the first place, the assembly may be prepared of a first pair of guide rails 1 a and 2a, struts 4 and safety ropes 5a and Sb in the above described manner, and excavation of the prescribed ground area may be made without timbering to a depth of about 1 m. Then, the assembled pair of guide rails will be hung down into the cavity formed in the ground, followed by applying a rail protector over each rail head and pressing the rails at their heads by for example the bucket of an excavator until the rails are penetrated deep enough into the ground to possibly stand erect by themselves. Then, the lower wall panel 6b is assembled with the side end plate of one side end thereof inserted by fitting into the longitudinal panel receiving portion 27 (Figs. 1 6 and 1) of self-standing guide rails 1 a and 2a.

In a same manner as the above assemblaged guide rails 1 a and 2a, preparation may be made of a next assembly of guide rails 1 b and 2b, separately, and the assembly may be hung down with the side end plate of the other side end of panel 6b slidably received into the panel receiving portion thereof. Guide rails 1 b and 2b may be driven into ground to the prescribed depth, and when the top ends of guide rails 1 a, 2a, 1 b and 2b become substantially equally high above the ground, the setting of a first span is accomplished, of the temporary soil-retaining wall structure according to the present invention.

Then, a panel protector will be applied over the extension of the upper edge of the lower panel 6b, and the ground area lying between the set pair of panels 6b and 6b is ditched. As the digging operation progresses, the depth to which the guide rails were penetrated through the ground becomes increasingly insufficient, so that the degree of restraining of safety ropes 5a and 5b should be carefully viewed at so as to have the rails and panels be further driven into the ground at opportune times in an optimum manner.

When digging as above has been made to a depth substantially corresponding to the height of panels 6b, the panel will be pressed down, and the panel connecting member 15 will be planted into the vertical reinforcement pipe or rib 11 of the panel. Then, an upper wall panel 6a will be placed by fitting between guide rails 1 a and 1 b and also between 2a and 2b, and as shown in Fig. 13, the panel connecting member 15 will be rotated to 900 by the spanner 26 engaged with the same through the notched portion 14 at the lower edge of the upper panel 6a, to accomplish an integral connection of lower and upper panels 6b and 6a.

Digging by an excavator will then be worked of the ground area at which temporary side walls were formed by the upper panels 6a and 6a. At this stage of operation, digging may also be made in preparation for planting a next pair of guide rails 1 c and 2c (not shown).

The foregoing series of excavation steps may be repeated to accomplish the digging of a trench or the like of the prescribed depth and length, and when installation in the trench or the like has been made of such as for example concrete pipes, cables, water-supply pipeline, box culverts and so forth, the temporary wall structure will be removed by pulling out and back filling of the trench with soil will be operated.

As illustrated in Fig. 20, the metal fixture 28 (32) at the end of strut 4 is pivotally secured through pin 33 to the joint piece 21 of guide rails 1 a, 1 b, 2a and 2b. Also, as shown in Fig. 21, the abutting faces of coupling 30, turnbuckle 29 and supporters 31 can undergo abutting at the compensationally tapered faces, and in addition, those members are formed to be an integral body through pins 34. Thus, in case of a difference in the depth of penetration of a pair of guide rails disposed respectively at left and right sides of an excavation to be ditched, the arrangement of the pair of rails and two struts extended between the rails can undergo deformation maintaining a parallelogram with respect to the shape encompassed by such two rails and two struts, as before mentioned.Also, any pressure of soil tending to be applied externally through wall panels is transmitted through a line-to-line contact between the surface of the end metal fixture 28 (32) and the inner wall of the wall panel. As before stated, the metal fixture 28 (38) of the strut 4 is pivotally connected to the guide rail through pin 33, so that the strut 4 can be free of the application of any force other than a compressive stress applied in the axial direction thereof, whereby it can well be of a relatively small size and yet can stand for a relatively high pressure of collapsed ground or soil.

With use of the retaining temporary wall structure of the present invention, excavation of a highly particular trench or the like can be efficiently worked.

For example, as shown in Fig. 23, excavation can be made of a channel or trench which has a stepped structure in cross section and in which an upper and a lower pipelines P1 and P2 are installed in an accordingly stepped arrangement.

As hereinbefore recited, it is required according to the present invention that upon completion of the trench excavation, installation of for example a pipeline along the bed of the trench and back filling of the trench, the temporary wall assembly is decomposed and pulled out of the ground, and a description will now be entered in this respect.

Assembly removing device Removal of wall panels once planted in the ground may be carried out by applying a rope in engagement with the hook member provided at an upper side end portion of the panel and lifting the panel with use of a crane or the like. However, panels are then subject to application of a considerably great soil pressure, and there lies friction resistance of a relatively great strength present along surfaces of panels and guide rails.

Particularly, at an outset stage of the panel removing operation, the required force of pulling is considerably great, whereby a crane to be employed has to be of an accordingly great capacity; in addition, not only the operation is highly troublesome, but also is it likely that a difficulty on safety is involved in fulfilling the operation.

In the circumstances, it is intended with the assembly or panel removing device according to the present invention that it can exert a sufficiently great power of pulling particularly at an initial stage of the pulling-out operation when a relatively high friction resistance is likely to be presented and can therefore dispense with a crane of such a large capacity as heretofore been unavoidably required of a crane, and also that it is relatively small in size and simple in structure and yet can effectively curtail the required operation time and assure safety for the operation.

Such device according to the present invention, which is particularly for pulling out the wall panels from the ground into which they have been temporarily planted, broadly comprise a hanger engageable with the hook member of the panel, a support base engageable with the panel and supporting the hanger in the prescribed position, and a jack for lifting the hanger either or not through the support base. A specific embodiment of this device is illustrated in Figs. 24 and 25.

Referring now to Figs. 24 and 25, which respectively show a front elevational view and a side elevational view of the device for removing or pulling out panels, therein the device indicated at 40 includes the hanger 41, support base 42 and hydraulic jack 43. The hanger 41 comprises a bracket 44 and link 45, and at the opening 46 provided in the vicinity of its lower end, the hanger bracket 44 is engaged with the hook member 17 integrally secured at an upper side end portion of the wall panel. At its upper end portion, the hanger bracket 44 is suspension connected to a lower end portion of the link 45 through a connecting pin 47. Also, the link 45 is suspension connected to the support base member 42 through a pin 48.

The support member 42 comprises a skeleton member 49 and side plates 50 and can be mounted on the panel 6a. The skeleton 49, which has a channel or grooved cross section is formed to be substantially horizontal at its upper and lower end faces and inclined in its intermediate portion upwardly from the lower end toward the upper end. Also, the skeleton is contacted at its lower end face with the upper edge surface of panel 6a. The lower end portions 51 of side plates 50, which are fixed to the skeleton, are extended downwardly beyond the lower end of the skeleton to embrace an upper end portion of the panel 6a at both sides of the latter. Further, to the lower face of a top end portion of the member 49, a backing metal member 52 is attached, with which the top end of rod 53 of the hydraulic jack 43 mounted on the top end face of guide rail 1 comes into contact when the rod is extended.

In pulling out the panel 6a with use of the device 40, the support base 42 will be mounted on the top end face of one of parallel disposed two panels 6a to be pulled out and the jack 43, on the top end face of guide rail 1. The opening 46 of hanger bracket 44 will be engaged with the hook member 1 7 of the panel 6a. A same operation as above may be effected in connection with another panel 6a of the pair and its associated guide rail 1.

Then, the distance between the support base 42 and the rod 53 of jack 43 will be suitably adjusted, and also a suitable adjustment will be effected so that the two hydraulic jacks 43 may synchronously function relative to the two support bases 42. When such condition is met, panels 6a will be hung up by a crane at a central portion of each panel (not shown) and, at the same time, the jacks will be put into operation to push up the support bases 42. Thus, at an initial stage of the panel removal operation it is that pulling up of panels by a crane and that by the function of jacks are operated together at the same time, and as soon as a subsequent stage of the operation is reached when the rod 53 of jack 43 has arrived at a maximum value of its extension stroke, pulling by the crane alone will be initiated.At this stage, the support base 42 may be left as mounted on panel 6a and lifted together with the latter, and when panels 6a have been pulled up to a certain greater height, the operation of the crane may once be suspended to dismount support bases 42 and hangers 41, followed then by resumption of the operation of crane to accomplish removal of panels.

In the above described specific embodiment of the present invention, although a hydraulic jack is employed for means for aiding in the pulling out of panels by a crane, it also is feasible to employ any other suitable means in place of the hydraulic jack, for example such as a power driven screw jack or the like.

As described in detail in the foregoing paragraphs, the soil-retaining temporary wall structure according to the present invention is possessed of the following characteristics.

A first characteristic resides in that the structure basically includes four (4) guide rails 1 a, 1 b, 2a and 2b employed as a unit or set, a plurality of struts 4 connected through pins to the pair of left and right rails 1 a and 2a or 1 b and 2b, and safety ropes such as wire ropes, 5a and 5b, extended between said pair of guide rails in a manner of being inclined in mutually crossing directions. With the structure of the invention having such characteristic in assemblage, when one of the pair of guide rails undergo a displacement relative to the other, either of the safety wire ropes 5a and 5b can undergo straining to control the amount of the relative displacement of the two guide rails, whereby it can be effectively checked that either of the pair of guide rails alone is permitted to be excessively driven into the ground.

A second characteristic consists in that the strut 4 composed of a plurality of members assembled in a straight linear arrangement includes a turnbuckle, which may be suitably operated to change the distance between the pair of left and right guide rails and accordingly adjust the distance between two panels to be parallel disposed, proportional to a particular width of a trench or the like to be excavated.

A third characteristic lies in that the abutting faces of component members of the strut comprise compensationally tapered faces, which abut against one another to strongly bear against any compressive force applied to the strut, whereby the strut can have an increased rigidity, suppress to minimum its propensity to deflection, and stand for a relatively high soil pressure to be applied to panels.

A fourth characteristic is concerned with the provision of the panel connecting member of a simple structure between upper and lower panels to integrally connect the panels together. With the arrangement according to the present invention, the wall panels can be free of a connecting member exposed above their surfaces, and they can be freely connected together or disconnected apart.

The soil retaining wall structure according to the present is simple in structure and has various characteristics as recited above, and it can with ease be assembled, planted and decomposed to its component members, whereby it is highly conducive to enhancing the operation efficiency for excavation works.

Claims (7)

1. A soil-retaining wall structure comprising at least two pairs of guide rails, two guide rails of each pair being disposed one at a side and the other at the other side of an excavation such as a trench or the like to be formed, at least one strut connected at the ends thereof to the pair of guide rails to support a load applied through guide rails, at least two safety ropes individually having a length greater than the distance between the pair of guide rails and connected at the ends thereof to the pair of guide rails in a manner of being inclined in mutually crossing directions, and wall panels received by fitting between two guide rails disposed adjacent to each other in the longitudinal direction of said excavation to be formed.

2. A structure as recited in claim 1, in which said safety ropes are provided in a mutually crossing arrangement between the pair of guide rails in a manner such that in case one of the pair of guide rails undergoes a certain degree of displacement in its longitudinal direction relative to the other, one of the safety ropes undergoes straining to control the amount of relative displacement of the guide rails.

3. A structure as recited in claim 1, in which said strut is connected through pins to the pair of guide rails in a manner such that the pair of guide rails are permitted to undergo displacement relative to each other.

4. Structure as recited in claim 1, in which said strut includes a turnbuckle.

5. A structure as recited in claim 1, in which said wall panels comprise an upper and a lower one, which are disengageably connected together through a panel connecting member.

6. A structure as recited in claim 1, in which said strut comprise a plurality of members and are contacted at cylindrical ends thereof with the pair of guide rails, at least one of said plurality of members being displaceable relative to an adjacent member or members and abuttingly engageable with said adjacent member or members through compensationally tapered faces at least at one portion thereof connected to the adjacent member or members.

7. A soil-retaining wall structure substantially as hereinbefore described with reference to the accompanying drawings.