US1835665A - Method of installing sheet piling - Google Patents

Description

Dec. 8, 1931. A. P. MILLER METHOD OF INSTALLING SHEET FILING Filed June 15, 1931 2 Sheets-Sheet l iNVENTOR D86. 8, 1931 p I 1,835,665

METHOD OF INSTALLING SHEET FILING F le J ne 1931 2 Sheets-Sheet 2 Patented Dec. 8, 1931 FATENT QFF CE METHOD or rnsTA L Nesnrm FILING Ap li ation me Jan '15 The present invention is concerned with a method of installing sheet considered from one asp ct capable of a wide and varied range of utility in connection with sheet piling installations regardless of the purpose for which the piling is to used,

Considered from another hovvever,

the invention is generically concerned with the provision of a n ethodiof sheet piling installation \vhich vvill obviate the need for shoring or under-pinning abuilding during the P e s of i gi al e c? ati adiee t thereto. w i

In other ords, whilethe method of piling installation completely obviates the present undesirable methods of jetting or driving the sheet piling, it is unique in that it is the only method thus far devised forelfeqtively eliminating the need for under-pinning or shoring \vhere an excavation is to be made deep or deeper thaithe footings of :adjacentstanding structures. i

Driving methods of installing sheet pilings create vibration Waves which spreadto adjoining foundat ons, causing settlement,

crackinglor crumbling of these foundations.

Also, the norse .att ending".such' percussive means of installingsheetipilings quite annoying. I i l v Water jetting methods of installing any type of piling's are frequently disa dva ntageous inasmuch as they cause 'settlement of the surrounding soil, and thereby endanger the foundations oiisurrounding structures. Such methods also entail the use of ,puiiiping units for creating high pressure jets and the splashing and splatteringof the ater attending such a method causes a messy condition around the construction region.

An object of the present invention therefore is to provide a method by which sheet pilings may be installed .in asi npleand inexpensive manner without the use ofeither driving or jetting apparatus which might subject the soil to excessive vibrations, or cause undesirable settlement thereof.

Another object is to provide amethod of installing foundations closely adjacent a previously erected building wherein sheet e s 'tiqn f Pi i is pl e 1S us d and 1:13;- e e ec- 24 4- pre tested as it is installed, the pretesting being suliicient to determine Whether or not the individual sheet piling'sections are capable of sustaining their share of the load which will be eventually transmitted "as them through the soil by the adjacent structure Another object' 'of the invention isto provide a method 01 piling installation wherein the possibility of displacement orcaving in the pretested sheet piling is further e1 bracing members which are appliedatinr tervals' as the excavation proceeds. These supplemental bracing members may be and theoretically are merely an added safety factor, but by utilizing them the span of tlile sheet piling in which flexing may occur is considerablylininimized. i

In carrying out my invention, Isinl; shafts one at a time in the soil along the boundary 1 line of the proposed excavation as by the use ot'conventional post hole angers. The sllfiit pilings which are a vidthcorrespondinga}? proximately to the diameters ofthe shafts or holes are then dropped into the their lower ends embedded in the soil .to afford a toe-hold. The topportions of the edge keyed pilings are then braced against lateral movement'by the use of a ivaler,"or the like, and the cavities defined by the outside c surfaces of the pilings and the correspondouter Wallsof the $11; ts are filled in with part or the previously removed soil or other "suitable material. This filler material is tamped or otherwise compacted,

ivill exert a v ing toivard the area to be excavated so that these pilings will be stressed sufiiciei tlyt o counteract'the effectof pressure exerted by surrounding structures. l After the sheet pilings have been so installed a-11dpretestcd,tl1e excavation can then be started, the intermediate portions of the sheet piling being further braced against unduednward flexing as the excavation proceeds. In otherhwo'rds, having installedand vpretested the sheet piling as to its load carryability, and having thus ascertained the fact that the sheet piling'will sustain the load, even when flexed throughout the entire ided against by the use of suppleiiiel ital holes with so that it R ..1 '1 '1 lateral piessuieon saic. saee p1 length -:of its span Ibetween waler at the surface of the ground and the bottom emheddedportion thereof, an added safety factor is provided by the installation of lateral bracing members emplaced as the excavation proceeds, these bracing members serving to subdivide the maximum flexed span of the piling into a plurality of smaller spans which can even more effectively sustain the load of the adjacent structures. Preferably the nature of the bracing structure is such that it would sustain the loads transmitted laterally and downwardly through the soil, even though the sheet piling was unkeyed, and even though it had no toe-hold.

This method of eliminating shoring and underpinning, while capable of use in any type of soil, is peculiarly adapted for use in water-bearing sand, such for instance, as beach sand, since the pretesting of the piling is materially expedited due to the facility with which the sand may be packed in behind the pilings and tamped for pretesting purposes. Furthermore, the installation of a foundation in water-bearing sand where conventional well points are used to dewater the sand at the excavation site, is conducive to an actual flow of sand under asubadjacent structure toward the excavation. In the present instance, the sheet piling, while permitting thefree flow of water toward the Well points from which it was pumped to dry the soil, acts as a positive preventative of the flow of sand with the water.

In the accompanying drawings, there is shown for the purpose of illustration, one specific form by which the present inventlon may be carried out. In these drawings Fig. '1 is a diagrammatic top plan view of the proposed excavation region adjacent a standing structure.

Fig. 2 is a section taken onthe line 22 of Fig. 1, and showing the lines of force radlating from the foot of structures ad oining the excavation.

section of the sheet piling in position.

Fig. 5 is a section transverse to that shown in Fig. 4, and showing the soil packed in behind the pilingsection to pretest the latter.

Fig. 6 is a vertical section through an area in which the excavation has already been accomplished, and V Fig. 7 is a section taken on line 77 of V Fig. 6, and showing the process of concreting the wall of the completed excavation.

In Figs. 1 and 2, I have shown the area A representing the area of the proposed excavation, this area. being adjacent a heavy standing structure, such as the building B.

The weight of the building B is distributed through the soil as a force acting approximately in the directions indicated by the lines C, it being understood that the particular angle of load distribution through the soil will be determined to a large extent by the nature of the soil itself. The forces acting through the vertical plane indicated by the heavy line D, which represents that proposed wall of the proposed excavation nearest the building B, would tend to cause the soil under the footing of the building B to move laterally into the excavated area when the reactionary forces exerted by the soil itself, are destroyed by the process of excavation. Consequently some means must be provided either to support the footing of the building A during the period of excavation, or some other means must be provided for effectively counteracting the forces indicated by the lines C and thereby preventing inflow of soil into the excavation and settlement or collapse of the building.

Prior to the present invention, it has been customary either to underpin the building where the excavation was to be made considerably deeper than the footings of the standing structure, or to support the building by shoring orequivalent bracing means.

Insofar as I am aware, the use of sheet pilings to line the walls of the proposed excavation for the purposes of preventing undermining or settlement of an adjacent structure, has not heretofore been satisfactory or safe, principally because there was no method of safely utilizing such pilings with any assurance thatthey would prevent collapse of the excavation or settlement of the building. Furthermore, the methods which have been previously used for installing sheet piling were in themselves not of a character which would permit'piling to be safely used in'lieu of underpinning or shoring. That is to say, the use of percussive means or of jetting means, might create disturbances in the soil under the standing structure and cause settlement thereof before excavation work was ever started. Furthermore, by prior methods of sheet piling installation, the engineers in charge of excavation, have not been able to assure themselves that the sheet piling would carry the lateral load imposed upon it since there has heretofore been no method of protesting the ability of the piling to carry the load.

pretested as an incident of its installation so that the ability of the piling to carry the load has been proven before any actual excavation work is started.

In accordance with the method, the first mamas step is to drill a shaft such as E with its center on the line D which is the side line of the proposed excavation. This shaft may be formed with an ordinary post hole digger or auger F, or by any other convenient means, the diameter of the shaft being substantially equal to the width of the sheet piling sect-ion to be installed.

The depth of this shaft would depend on the desired depth to which the excavation is to be made, but should preferably extend below the bottom of the excavation, since the bottom of this shaft would have a layer of loose soil collected thereat as the result of the falling or flow of this soil during the boring process and pile installation. Also, by forming a shaft E which eXtends below the bottom of the excavation, the lower portion of the sheet piling subsequently installed therein will have the lower end thereof firmly held and embedded below said bottom of the excavation, so that when the excavation is accomplished, the lower end of the sheet piling will still be retained in firm. anchored position. A small amount of soil may be dumped in and tamped if desired, to form the toe hold.

After the shaft E has been formed in the soil, a sheet piling G is lowered therein. Although this sheet piling may be of wood or concrete. it is preferable, for the purpose of the present invention, that it be made of steel, and may be of the usual form having means along the edges thereof for interlocking it with or keying it to adjacent sections. The sheet piling G is disposed in the shaft E in substantially vertical position and the lower end thereof embedded in the soil at the base of said shaft. Since the soil at the bottom of the shaft E includes loose soil which has fallen or flowed therein during the formation of said shaft or fallen during placing of pile, the lower end of thesheet pilings G will be very easily embedded in this loose soil. If desired, pressure may be applied to the upper end of the sheet piling to embed the lower end of the piling in the firm compact ground.

Furthermore, the momentum and weight of the steel piling as it is dropped into the excavation, causes the foot of the piling to embet itself in the soil, usually .to a sufficient extent to form an effective toe-hold. It will be understood that the weight of the building will be ineffective to cause collapse of the walls of the shaft E due to the fact that the soil which encircles this shaft has a true arch effect and efficiently carries the weight of the buildin A number of these sheet pilings E may be similarly installed by boring a'correspondnumber of shafts sufiiciently close to each other to permit interengagement of the 'longitudinal edges of adjoining sheet pilings disposed therein. After-a number of-such sheet greater resultant stress from the pro exerted by the structure B,.and also have a pilings have been installed, the upper ends thereof may be maintained in aligned anchored position, and braced against inward deflection towards the excavation region A by a suitable bracing member such as a wale piece H.

After the sheet pilings G have been so installed, the spaces J defined by the outer faces of said sheet pilings and the corresponding walls of the shafts E are filled with packing material. Although these spaces J may be filled before the upper ends of the piliugs are braced and anchored in position, it is preferable that both ends of the pilings be anchored in position before the filling operation is begun. The filler material may consist of soil previously taken from the boring of the shaft E, or if desired, a dry mixture of COL- c ete may be substituted. This filling material in the spaces J is then packed very firmly in order to stress the sheet pilings suliiciently for them to exert reactionary forces WAlCll balance the forces created by the structure B. For that purpose, the filling material may be packed by means of a standard tamping tool, a piece of lumber, by the puddling of water, or by other similar means. The stress exerted by the packing of this filling material in the spaces J will cause slight defiections of the pilings, the span of the defied tion being determined by the distance between the wale piece H and the toe hold of the piling in the soil, shown somewhat exaggerated in Fig. 5.

If desired, as each shaft is bor d and the piling G disposed in place, the space J associated therewith may be filled and the material packed before boring an adjoining shaft. In any event, too many of these shafts should not be bored and left unprotected the same time, for a plurality of unprot cred shafts,

particularly adjoining shafts, might permit movement of the soil under the pressure action of the adjoining structures.

After the sheet pilings G have been installed in position as shown in Fig. 5, the excavation of .the area A may then be started. It should be noted that during the process of installing the pilings as shown in 5, some of the soil will probably have I owed or fallen intoadj oining relationship with the inside surface of these sheet piles. Under these conditions, this soil would tend to react against the forces created by the structure B. and serve, therefore, to decrease the degree of deflection of the sheet pilings G. The absence of the reactionary forces caused by the removal of this material during e1;- cavation, may subject these sheet pilings to tendency'to throw these pilings out of alignment. It may therefore, be desirable as the excavation proceeds downwardly, and as the material is removed fromcontact with the inside surfaces of said pilings, to compensate for such removal by bracing the intermediate portion of these pilings. For that purpose, the inside surfaces of the sheet pilings are braced by Wale pieces-K or other suita- 'ble bracing members disposed adjoining the inside surfaces-of the sheet pilings G, and urged into engagement with these sheet piling surfaces by means of timber bracing members L as shown in Figs. 7 and 6.

The ability of the Wale pieces K to effectively sustain the piling against further buckling, may also be pretested by driving wedge members M between the walers and the inside surface of the sheet pilings.

As the excavation proceeds downwardly and additional wale pieces and bracing members are employed, the span of deflection of the pilings is reduced. That is to say, during'the original pretesting of the piling, the latter was free to flex throughout the entire span between the surface waler and the toe hold, whereas the addition of other Wale pieces during the process of excavation gradually cuts down this large deflection span and subdivides it into a plurality of smaller spans, adding a further safety factor.

After the excavation of the region A has been accomplished, it may be desired to line the excavated region with concrete as is customary in the building of foundations. For that purpose, the sheet pilings may be-retained in position, and a concrete wall formed adjacent the inside surfaces of these pilings.

In Fig. 7, is shown the excavated region A in the process of being lined with a concrete foundation. The concrete foundation wall N is shown constructed adjacent the lower portions of the sheet pilings. After this wall has been formed to a height close to'the lower bracing members, L and M, and has been hardened sufficiently to sustain the sheet pilings against the inward pressure exerted by the soil on the outer surfaces of said pilings, these lower bracing members may then be removed, the wall N, under these conditions compensating for the removal of these lower bracing members. After these lower bracing members have been removed, the building of the wall N upwardly, is continued until the next bracing member is reached. The new addition to the concrete wall N is then permitted to harden, and the next bracing members right above it removed. This process is continued until the desired concrete foundation wall on the sides of the excavated region, has been formed. In this manner, the pilings G are retained in braced position, during the laying of the foundation wall, and the soil outside the excavated area supported'against settlement.

It should be noted that by means of my improved method, the installation of sheet pilings. is accomplished Without endangering .the foundations of adjoining structures.

Also the method is simple and inexpensive, and does not create the messy and noisy conditions incidental to the installation of pilings by present methods.

From the foregoing description, it will be apparent that the method is peculiarly effective for eliminating under-pinning and shoring when making a foundation near astanding structure; Entirely aside from such use, however, the method of piling installing herein described, may be carried out for open trench workin the fields, and in locations where-the problem of lateral displacementof the soil is slight, since the method in any event, eliminates the need for the cumbersome, expensive apparatus which is usually difficult to transport into out-of-theway localities.

The invention is susceptible of use in connection with various types of soil, but it has certain unique advantages when utilized in beach sand, particularly water-bearing sand which has been dewatered and which is substantially incompressible and flows freely if rewatered. Among these advantages are the facts that driving of any type of piling in such sand is'extremely diflicult and that the sand is a particularly effective medium for packing and pretesting the piling and the tamping of this material, which may be simply accomplished by'pouring water thereon. I claim:

1. The method of installing sheet pilings along a proposed line of excavation, which includes the steps of forming substantially vertical shafts along said line of excavation, disposing the sheet pilings in said shafts, and disposing a filler in the cavities formed between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts.

2. The method of installing sheet pilings along a proposed line of excavation, which includes the steps of drilling substantially vertical shafts along said line of excavation, said shafts extending to a depth below the bottom of the proposed excavation, disposing the sheet pilings in said shafts, and disposing a filler in the cavities formed between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts.

3. A method of installing sheet pilings along a proposed'line of excavation, which includes the steps of forming shafts along the proposed'line of excavation, disposing the-sheet pilings in said shafts insubstantially vertical position, disposing a filler in the cavities formed between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts, and packing said filler so that said filler exerts a lateral force on said sheet pilings suflicient for said pilings to exert reactionary forces which balance the forces created by adjoining structures.

4. The method for installing sheet pilings along a proposed line of excavation, which includes the steps of forming along said line of excavation shafts, extending to a depth below the bottom of the proposed excavation, disposing the sheet pilings in said shafts, and anchoring the ends thereof in substantially vertical position with the lower ends thereof extending below the bottom plane of excavation, disposing a filler in the cavities between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts, and packing said filler, so thatit exerts a lateral force on said sheet pilings.

5. The method for installing sheet pilings along a proposed line. of excavation, which includes the steps of forming substantially vertical shafts along the proposed line of excavation, disposing the sheet pilings in said shafts, filling the cavities formed between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts with loose material, and bracing the upper ends of said sheet pilings to prevent these upper ends from moving out of alignment, and from deflecting inwardly towards the proposed region of excavation.

- 6. The method for installing sheet pilings along a proposed line of excavation, which includes the steps of drilling shafts substantially vertical along said line of excavation, disposing the sheet pilings in said shafts, disposing a filler in the cavities formed between the outer surfaces of said sheet pilings, and the corresponding outer walls of said shafts, and excavating and bracing the intermediate sections of said sheet pilings at intervals against undue inward flexing as the excavation uncovers said intermediate sections.

7. The method for installing sheet pilings along a proposed line of excavation, which includes the steps of drilling shafts substantially vertical into the soil, disposing the sheet pilings in said shafts, and disposing the material recovered from said shafts into the cavities formed between the outer surfaces of said sheet pilings and the corresponding outer walls of said shafts.

8. The method of constructing a foundation, which includes the steps of drilling shafts into the soil along the proposed line of excavation, disposing sheet pilings in said shafts with the bottoms thereof embedded in the soil, disposing a filler in the cavities formed between the outer surfaces of the sheet pilings, and the corresponding outer walls of the shafts, anchoring the ends of said sheet pilings in position, excavating and reinforcing the intermediate portions of the sheet pilings by bracing members as the excavation proceeds, building a concrete foundation wall in sections adjacent the sheet pilings, and removing the bracing members associated with said pilings, each concrete wall section extending vertically between adjacent reinforced portions of said pilings, and being built and hardened successively, sai bracing members being removed only when the adjacent concrete wall section just below them have hardened sufficiently to structurally compensate for the removal of these bracing members.

Signed at Pleasantville, in the county of Atlantic and State of New Jersey, this 11th day of June A. D. 1931.

ANTHONY PAUL MILLER.

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