GB2346917A

GB2346917A - Piling system with continuous load measurement

Info

Publication number: GB2346917A
Application number: GB9930254A
Authority: GB
Inventors: Robert Tjhing Bo Oei
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-12-22
Filing date: 1999-12-21
Publication date: 2000-08-23
Also published as: GB9930254D0; SG102542A1

Abstract

A piling system with continuous load measurement is disclosed which includes a tubular pile formed from segments 11 and a mandrel 12 located movably within the tubular pile 11 and extending through the length thereof. A driving shoe 15 is driven by the tubular pile 11 and/or the mandrel 12 into the ground. The driving shoe 15 is selectively engaged by the mandrel 12 and/or the tubular pile 11. The system is adapted to prevent the tubular pile 11 from being overloaded and to enable the separate toe end bearing resistance (Q) and frictional resistance (P) and P+Q measurements of pile loading to be made. Upon the desired resistance being achieved, the mandrel 12 is removed, and the tubular pile 11 is filled with reinforcement and concrete material.

Description

PILING SYSTEM WITH CONTINUOUS LOAD MEASUREMENT This invention relates to a foundation piling system that is driven into the ground, preferably by hydraulically jacking against a counterweight, with continuous load measurement.

A pile is a load bearing structure that is installed deep in the ground. In general, piles are required to act as the foundation that carries the load from the superstructure and transmits such load into the competent soil strata. However, there are piles that are required to carry a combination of compressive axial and transverse loads, or axial tensile loads. Thus, understanding the functional performance of the pile is most important in the selection of a piling system. The different known piling systems may be categorized as prefabricated or cast in-situ piles. Prefabricated piles, as the name implies, are prefabricated structural elements made of concrete, steel or other durable materials, which are nomally driven into the ground. Under this category are the pre-cast concrete piles, preformed steel piles, timber piles, etc. Cast in-situ piles are piles formed by casting concrete into preformed bores or excavations in the ground. Cast in-situ piles include bored piles, caissons, barettes, and grouted micro-piles.

The prefabricated piles are usually installed by driving or jacking the same into the ground until a desired resistance is achieved. The piles may be driven into the ground by utilizing the impact energy of a dropped hammer, steam or air hammer, double acting diese ! hammer, hydraulic hammer, or vibration hammer. Alternatively, the prefabricated piles may be forcibly jacked into the ground by hydraulic jacks, or aided by water jetdng to destroy the soil resistance. Sometimes, prefabricated piles may be inserted into preformed holes prior to driving or grouting, for example due to the existence of a very hard soil layer that could not be penetrated by normal driving Driven piles suffer from the direct impact energy of the drivina hammer, as well as the reflected energy wave, particularly during hard driving.

Piles derive their capacity to support the load from the interaction with the surrounding soil matrix. The load catrying capacity of the pile consists of the shaft friction P and the toe end bearing resistance Q. The surface envelope of the pile in contact with the surrounding ground mobilizes the frictiona ! resistance due to the : lateral earth pressure, and thereby disperses part of the axial load into the ground.

Whereas the pile toe gradually mobilizes the bearing resistance as the pile is displaced into the ground. In tension piles, only the friction resistance P of the shaft is considered in the design. In laterally loaded piles, the soil-pile interaction is much more complicated as the soil lateral resistance depends on the lateral displacement of the pile.

In general, the design capacity of the pile is computed from the estimated shaft friction and end bearing resistance based on the soil investigation data. For driven piles, the capacity is checked against the final set empirical energy formulae of the number of blows per unit penetration of the pile. Whereas for cast in-situ piles, it depends on the design soil parameters to justify the pile capacity. Only for jacked-in pile system is the load bearing capacity of the pile more precisely known. It must however be understood that the pile resistance is only mobilized when the pile experiences a displacement correlating to ground settlement. Therefore, the criteria of pile capacity is defined in terms of the load that the pile can safely carry within acceptable pile top elastic settlement limit.

Under the present practice of pile installation, except for hydrauIically jacked-in piles, there is no way to ascertain the pile capacity without conducting any load test. Therefore, the practice requires a certain number of load tests to be conducted to ascertain that the piles possess the designed capacity. However, it is impossible to test every pile, because of time, space and cost constraints. While computerized dynamic wave energy testing methods have been developed, the accuracy of such load test results depend on the assumed input parameters and the experience in interpreting the logged data. As piles form the fondation to support the superstructure, it is most desired that there should be a more precise way or method of determining each pile capacity, because any fondation failure could be catastrophic or costly to remedy. Also, as a result of the rising popularity of settlement compensating piles used in pile-raft foundation, there is a need for accurate pile load settlement data input for the computerized structural analysis and design.

A serious limitation of known load measuring practice is that only the total load of P+Q can be obtained. It is therefore desirable to be able to understand and predict the behavior of piles and to provide a load measuring system that is capable of continuously monitoring P and Q separately.

It is an aim of the present invention to overcome or substantially ameliorate at least some of the above disadvantages generally to provide an improved fondation piling system that can be driven by a double hydraulic loading jack mechanism and associated apparats and method, which will allow the continuous measurement of the shaft friction P and the end bearing resistance Q separately.

In accordance with a first aspect of the invention, there is provided a piling system for continuously measuring the shaft friction P and the bearing resistance Q of the ground, the system including: a tubular pile; a mandrel movably disposed within the tubular pile and extending substantially through the length thereof; and a driving shoe driven by one or both of the tubular pile and mandrel into the ground and adapted to be selectively engaged by the one or both of the mandrel and tubufar pile, the system being adapted to enable separate Q and P or combined (P + Q) measurements respectively.

Preferably, the tubular pile is driven into the ground by means of a main jack, the main jack being capable of selectively applying force to the mandrel.

Preferably, the mandrel is independently driven into the ground by a mandrel jack.

Preferably, the tubular pile is provided in segments, the segments being interconnected end-to-end by means of joint sleeves.

Preferably, the driving shoe is conical in shape and has an outer diameter substantially equal to the outer diameter of the tubular pile.

Preferably, the mandrel is concentrically disposed within the tubular pile.

In accordance with a second aspect of the invention, there is provided a method of measuring the load capacity of a piling system for measuring the shaft friction P and the toc bearing resistance Q of the ground, the system including a tubular pile, a mandrel and a driving shoe, the method including the steps of : driving one or both of the mandrel and tubular pile into the ground and separately measuring the load capacity of the mandrel and the load capacity of the tubular pile so as to provide separate Q and P or combined (P+Q) measurements respectively.

Preferably, during the measurement of Q, the driving shoe is moved downwardly and away from the tubular pile.

Preferably, the method further includes driving the tubular pile and mandrel simultaneously downwards and recording (P+Q) and Q, until (P+Q)-Q is equal to the allowable comprcssive force in the tubular pile.

Preferably, the method further includes plotting (P+Q), Q, and (P+Q)-Q versus pile penetration on a graph.

Preferably, the method further includes driving the tubular pile and mandrel alternately to limit the stresses experienced in the tubular pile, and correspondingly recording P and Q separately.

Preferably, the method further includes plotting P, Q, and (P+Q) versus pile penetration on a graph.

Preferably, the step of driving the tubular pile and mandrel alternatively is continued until (P+Q) or Q has reached the required resistance.

In accordance with a third aspect of the invention, there is provided a method of installing a piling system into the ground, wherein the piling system includes a tubular pile, a mandrel and a driving shoe for measuring the shaft friction P and the toe bearing resistance Q of the ground, the method including the steps of : driving one or both of the mandrel and tubular pile into the ground ; making Q and P or (P+Q) measurements of the mandrel and tubular pile; and removing the mandrel from the tubular pile.

Preferably, the method further includes filling the tubular pile with reinforcement and concrete material.

Preferably, the Q, P and (P+Q) loadings are measured during installation through the use of a double hydraulic loading jack mechanism until a desired total resistance is achieved.

In accordance with a fourth aspect of the invention, there is provided a pile for enabling the measurements of the pile shaft friction P and the pile lead bearing resistance Q provided by the ground into which the pile is being driven, the pile including : a shaft body having an axial cavity coaxial with an axis along which the pile is driven and apertures at both extremities, wherein the axial cavity and apertures are in fluid communication ; a mandrel movably disposed within the axial cavity and extendable through an aperture at an extremity which leads the pile while the pile is being driven into the ground ; and a lead member coupled to the lead extremity, wherein the lead member engages at least one of the shaft body and mandrel for transmitting the Q to the at least one of the shaft body and mandrel.

Preferably, the shaft body is tubular.

Preferably, the mandrel is concentrically disposed within the tubular shaft body.

Preferably, the lead member is conical with the apex leading the pile being driven into the ground.

Preferably, the shaft body includes multiple segments of the shaft body having corresponding axial cavities, the shaft body being formed by coupling the segments end-to-end so that the segments are coaxial.

Preferably, the segments are coupled by joint sleeves.

Preferably, the outer circumferential surfaces of the segments and joint sleeves are substantially flushed.

Preferably, the lead member is movably coupled to the shaft body, the lead member being displaceable from the lead extremity along the piling axis.

Preferably, when the lead member is displaced from the lead extremity, the Q is transmittable co the mandrel which can be independently driven and thereby is independently measurable from the mandrel and the P is transmittable to the shaft body which can be independently driven and thereby is independently measurable from the shaft body.

Preferably, when the lead member abuts the lead extremity, the Q is transmittable LO both the shaft body and mandrel which can be simultaneously driven and thereby is measurable collectively with P through both the shaft body and mandrel.

Preferably, the lead member is removably engaged to the mandrel, the mandrel being disengageable from the lead member and withdrawable from the axial cavity through an aperture at an extremity of the shaft body opposite the lead extremity when the P and Q collectively reach a predetermined value.

Preferably, the axial cavity is filled with structural material upon withdrawal of the mandrel.

In accordance with a fifth aspect of the invention, there is provided a method of driving a pile into the ground and simultaneously measuring the pile shaft friction P and the pile lead bearing resistance Q, the pile having a share body with an axial cavity coaxial with an axis along which the pile is driven, and a mandrel movably disposed within the axial cavity, the method including the steps of driving the shaft body independently into the ground condition upon the mandrel being independently driven into the ground, and otherwise simultaneously driving the shaft body with the mandrel into the ground ; and measuring independently the Q from the mandrel, the Q being transmitted substantially independently to the mandrel.

Preferably, the driving step includes driving the shaft body independently, thereby enabling the independent measurement of the P from the shaft body, the P being transmitted to the shaft body.

Preferably, the driving step further includes driving the shaft body simultaneously with the mandrel, thereby enabling the collective measurement of P and Q from both the mandrel and shaft body, the Q being transmitted to both the mandrel and shaft body and the P being transmitted to the shaft body.

Preferably, the driving step includes driving, alternately and independently, the mandrel and shaft body when the P reaches a predetermined value due to the simultaneous driving of both the mandrel and shaft body.

Preferably, the method further includes driving the pile led by a lead member engaged with at least one of the shaft body and mandrel.

Preferably, the step of driving the pile led by the lead member includes transmitting the Q to the lead member then to the mandrel for the independent measurement of the Q, otherwise transmitting the Q to the lead member then to both the mandrel and shaft body.

Preferably, the method further includes withdrawing the mandrel from the axial cavity when the P and Q collectively reach a predetermined value.

Preferably, the withdrawing step includes filling the axial cavity with structural material.

A A preferred form of the present invention is now described by way of example with reference to the accompanying drawings, wherein : Fig. 1 is a schematic elevational view of the pile driving and load measuring system, and Fig. 2 is the graph of P, Q and P+Q loading and time versus pile penetration.

As used herein, the leaer"Q"is intended to define the toe bearing resistance of a pile according to a preferred embodiment of the invention. The letter"P"defines the shaft friction resistance applied by the surrounding soil matrix to the external surface of the pile. The expression"F+Q"defines the combined total of the toe bearing and shaft friction resistance of the pile.

In Fig. I of the accompanying drawings there is schematically depicted a pile system 10 including prefabricated pre-cast tubular pile segments 11 and a prefabricated steel driving shoe 15 at the lower end of a lowest or bottom tubular pile segment lla. The driving shoe 15 is typically conical in shape having an outer diameter equivalent to the outer diameter of the tubular pilc 11. Within the tubular pile 11 there is loosely placed a mandrel 12, the bottom end of which bears against the upper surface of the driving shoe 15.

The individual segments of the tubular pile 11 are fitted together by means of joint sleeves 14 which provide for lateral stability and axial continuity of the adjoining portions of the respective tubular pile segments 11. That is, each of the tubular pile segments 11 have an annular external recess at its respective end, the recesses being adapted to receive the joint sleeves 14. The outer diameter of the joint sleeve 14 is preferably equal to or less than the outer diameter of the tubular pile segments 11.

The lower extremity of the bottom pile segment Ila has a similar annular recess that is received by an annular socket sleeve 15a formed at the upper surface of the driving shoe 15. Preferably the driving shoe 15 is displaceable from the bottom end of the tubular pile segment I la for the purpose of enabling a reading of a Q measurement without becoming disjointed. The extent by which the driving shoe 15 is displaceable from the bottom end of the tubular pile segment 1 la is indicated by the letter"G"in Fig. 1.

In order to drive the tubular pile segments 11 (hereinafter generally refer to the tubular pile segments 11 coupled by the joint sleeves 14) into the ground, a main jack 13 is provided. The main jack 13 can provide a thrust Top,. the tubular pile seomenrs 11, or a thrust Tp Q to both the tubular pile segments 11 and the mandrel 12. The main jack 13 may or may not apply force to the mandrel 12 through a mandrel jack 16. The mandrel jack 16 applies a thrust TQ to the mandrel 12 without applying any force to the tubular pile segments 11, until the mandrel 12 has moved a distance G.

Thereafter the main jack 13 exerts TP+Q to drive both the tubular pile segments 11 and the mandrel 12 simultaneously, allowing the mandrel jack 16 to monitor TQ.

Alternatively, when Trffl-TQ is equal to the allowable compressive force in the tubular pile 11, the main jack 13 and the mandrel jack 16 operate alternately measuring Tp and TQ separately.

The prefabricated tubular pile segments 11 are formed of high quality concrete or other suitable strong material. The tubular pile segments 11 could bc tested in the prefabrication yard even before being transported to the work site, therefore ensuring the structural quality of the pile. The annular socket sleeve 15a of the driving shoe 15 is made to fit the recess at the bottom of the tubular pile segment I Ia.

The driving shoe 15 is preferably directly attached to the mandrel 12 so as to transmit the toe bearing resistance Q to the mandrel 12. This is done to allow the measurement of Q load by the mandrel jack 16 connecte to the top of the mandrel 12. The driving shoe 15 can be advanced independently of the tubular pile segments 11 for a limited distance G, and thus preventing the tubular pile segments I 1 from being overstressed during driving.

The mandrel 12 is withdrawn from the tubular pile segments 11 only after the pile has been driven to achieve the required P+Q resistance. The void in which the mandrel 12 is disposed is Fi I led with concrete and reinforced with steel cage either for the top portion or the whole length of the tubular pile segments 11 if required. The steel reinforcement cage is embedded and protected within the tubular pile segments 11 and can be designed to resist any tensile load if the pile is to function as a tension pile with assured geotechnical capacity.

The method of installing the pile system 10 involves the assemblage of the prefabricated tubular pile segments 11 preferably concentric with the heavy steel mandrel 12, with the steel driving shoe 15 preferably attached to the lower end of the mandrel 12. The prefabricated tubular pile segments 11 are joined to each other by means of fitting steel sleeves 14 coated with adhesive paste in between adjoining tubular pile segments 11.

At the top of the mandrel 12, there is a hydraulic jack 16, which is mounted onto the main hydraulic jack 13. The main jack I3 is capable of driving both the tubular pile segments 11 and the mandrel 12. The mandrel hydraulic jack 16 measures the toe bearing resistance Q, while the main hydraulic jack 13 measures the shaft friction resistance P or the total pile bearing resistance P+Q. If it should be desirable to increase the Q resistance, the mandrel jack 16 allows the driving shoe 15 to be advanced independently from the tubular pipe pile 11.

During the jacking installation of the tubular pile segments 11, where the tubular pile segments 11 and the mandrel 12 are simultaneously driven by the main jack 13, the main jack 13 measures P+Q force, while the mandrel jack 16 measures Q force. When the main jack force P+Q less the mandrel jack force Q has reached the allowable compressive force in the tubular pile segments 11, the jacking system is switched to alternat driving between the main jack 13 and the mandrel Jack 12. The main jack 13 only advances the tubular pile segments 11 and measures the shaft frictional resistance P, while the mandrel jack 16 only advances the driving shoe 1S and measures the toe bearing resistance Q. Hence the tubular pile segments 11 is nnt to be overstressed beyond the allowable compressive force.

When the main hydraulic jack 13 has run out of stroke, additional lengths of the mandrel 12 and tubular pile segment 11 are inserted between the top of the installe tubular pile segments 1 I and the mandrel jack 16, after the main jack 13 piston is retracted.

An advantage afforded by the pile system 10 is that the pile system 10 the pile can be driven into the ground by means of the main jack 13 driving both the tubular pile segments 11 and the driving shoe 15 simultaneously, or alternatively, alternating with the mandrel jack 16 utilizing the same counterweight as rection.

An avantage of the present invention over prior art pile driving systems is that a continuous driving records of the shaft friction P and toe bearing resistance Q is enabled. Furthermore, the pile system 10 enables the limitation of the driving stresses in the tubular pile segments l l to allowable limits. The use of the pile system 10 also results in less noise pollution and is free of impact vibration comparcd to conventional driven piling systems. Associated with the pile system 10 is a degree of quality control achieved by way of the prefabrication process. Each pile capacity is hence assured by the continuous recording of P and Q.

Using the pile system 10 allows accurate individual pile capacity matching with the design load requirement, eliminates uncertainty in pile capacity and performance, improves load-settlement characteristics, and reduces pile ! cngth wastage. Furthermore, there is no longer a need for conducting pile load testing as each and every pile of the pile system 10 is effectively proof tested, resulting in a superior fondation pile system.

Claims

CLAIMS 1. A piling system for continuously measuring the shaft friction P and the bearing resistance Q of the ground, said system including: a tubular pile ; a mandrel movably disposed within said tubular pilc and extendinD substantially through the length thereof : and a driving shoe driven by one or both of the tubular pile and mandrel into the ground and adapted to be selectively engaged by said one or both of said mandrel and tubular pile, said system being adapted to enable separate Q and P or combined (P + Q) measurements respectively.
2. The system of claim 1, wherein said tubular pile is driven into the ground by means of a main jack, said main jack being capable of selectively applying force to said mandrel.
3. The system of claim 1, wherein said mandrel is independently driven into the ground by a mandrel jack.
4. The system of claim 1, wherein the tubular pile is provided in segments, said segments being interconnected end-to-end by means of joint sleeves.
5. The system of claim 4, wherein said driving shoe is conical in shape and has an outer diameter substantially equal to the outer diameter of said tubular pile.
6. The system of claim 1, wherein said mandrel is concentrically disposed within said tubular pile.
7. A method of measuring the load capacity of a piling system for measuring the shaft friction P and the toe bearing resistance Q oF the ground, said system including a tubular pile, a mandrel and a driving shoe, the method including the steps : driving one or both of said mandrel and tubular pile into the ground and separately measuring the load capacity of said mandrel and the load capacity of said tubular pile so as to provide separate Q and P or combined (P+Q) measurements respectively.
8. The method of claim 7, further including the step of moving said driving shoe downwardly and away from said tubular pile during the measurement of Q.
9. The method of claim 7, further including the step of driving said tubular pile and mandrel simultaneously downwards and recording (P+Q) and Q, until (P+Q)-Q is equal to the allowable compressive force in said tubular pile
10. The method of claim 7, further including the step of plotting (P+Q), P, and (P+Q)- Q versus pile penetration on a graph.
11. The method of claim 7, further including the step of driving said tubular pilc and mandrel alternately to limit the stresses experienced in said tubular pilc, and correspondingly recording P and Q separately.
12. The method of claim 11, further including the step of plotting P, Q, and (P+Q) versus pile penetration on a graph.
13. The method of claim 11, wherein the step of driving said tubular pile and mandrel alternatively is continued until (P+Q) or Q has reached the required resistance.
14. A method of installing a piling system into the ground, wherein said piling system includes a tubular pile, a mandrel and a driving shoe for measuring the shaft friction P and the toe bearing resistance Q of the ground, said method including the steps of : driving one or both of said mandrel and tubular pile into the ground ; making Q and P or (P+Q) measurements of said mandrel and tubular pile; and removing said mandrel from said tubular pile.
15. The method of claim 14, further including the step of filling said tubular pile with reinforcement and concrete material.
16. The method of claim 15, wherein the Q, P and (P+Q) loadings are measured during installation through the use of a double hydraulic loading jack mechanism until a desired total resistance is achieved.
17. A pile for enabling the measurements oF the pile shaft friction P and the pile lead bearing resistance Q provided by the ground into which said pile is being driven, said pile including: a shaft body having an axial cavity coaxial with an axis along which said pile is driven and apertures at both extremities, wherein said axial cavity and apertures are in fluid communication; a mandrel movably disposed within said axial cavity and extendable through an aperture at an extremity which leads said pile while said pile is being driven into the ground; and a lead member coupled to said lead extremity, wherein said lead member engages at least one of said shaft body and mandrel for transmitting said Q to said at least one of said shaft body and mandrel.
18. The pile as in claim 17, wherein said shaft body is tubular.
19. The pile as in claim 18, wherein said mandrel is concentrically disposed within said tubular shaft body.
20. The pile as in claim 19, wherein said lead member is conical with the apex leading said pile being driven into the ground.
21. The pile as in claim 17, wherein said shaft body includes multiple segments of said shaft body having corresponding axial cavities, said shaft body being formed by coupling said segments end-to-end so that said segments are coaxial.
22. The pile as in claim 21, wherein said segments are coupled by joint sleeves.
23. The pile as in claim 22, wherein the outer circumferential surfaces of said segments and joint sleeves are substantially flushed.
24. The pile as in claim 17, wherein said lead member is movably coupled to said shaft body, said lead member being displaceable from said lead extremity along said piling axis.
25. The pile as in claim 24, wherein, when said lead member is displaced from said lead extremity, said Q is transmittable to said mandrel which can be independently driven and thereby is independently measurable from said mandrel and said P is transmittable co said shaft body which can be independently driven and thereby is independently measurable from said shaft body.
26. The pile as in claim 25, wherein when said lead member abuts said lead extremity, said Q is transmittable to both said shaft body and mandrel which can be simultaneously driven and thereby is measurable collectively with P through both said shaft body and mandrel.
27. The pile as in claim 17, wherein said lead member is removably engaged to said mandrel, said mandrel being discngageable from said lead member and withdrawable from said axial cavity through an aperture at an extremity of said shaft body opposite said lead extremity when said P and Q collectively reach a predetermined value.
28. The pile as in claim 27, wherein said axial cavity is filled with structural material upon withdrawal of said mandrel.
29. A method of driving a pile into the ground and simultaneously measuring the pile shaft friction P and the pile lead bearing resistance Q, said pile having a shaft body with an axial cavity coaxial with an axis along which said pile is driven, and a mandret movably disposed within said axial cavity, said method including the steps of : driving said shaft body independently into the ground condition upon said mandrel being independently driven into the ground, and otherwise simultaneously driving said shaft body with said mandrel into the ground; and measuring independently said Q from said mandrel, said Q being transmitted substantially independently to said mandrel.
30. The method as in claim 29, wherein said driving step includes driving said shaft body independently, thereby enabling the independent measurement of said P from said shaft body, said P being transmitted to said shaft body.
31. The method as in claim 30, wherein said driving step further includes driving said shaft body simultaneously with said mandrel, thereby enabling the collective measurement of P and Q from both said mandrel and shaft body, said Q being transmitted to both said mandrel and shaft body and said P being transmitted to said shaft body.
32. The method as in claim 29, wherein said driving step includes driving, altemately and independently, said mandrel and shaft body when said P reaches a predetermined value due to said simultaneous driving of both said mandrel and shaft body.
33. The method as in claim 29, further including the steps of driving said pile led by a lead member engaged with at least one of said shaft body and mandrel.
34. The method as in claim 33, wherein said step of driving said pile led by said lead member includes transmitting said Q co said lead member then to said mandrel for the independent measurement of said Q, otherwise transmitting said Q to said lead member then to both said mandrel and shaft body.
35. The method as in claim 29, further including the steps of withdrawing said mandrel from said axial cavity when said P and Q collectively reach a predetermined value,
36. The method as in claim 35, wherein said withdrawing step includes filling said axial cavity with structural material.
37. A piling system substantially as hereinbefore described with reference to the accompanying drawings.

A method of measuring the load capacity of a piling system substantially as hereinbefore described with reference to the accompanying drawings.

A method of installing a piling system in the ground substantially as hereinbefore described with reference to the accompanying drawings.

A pile substantially as hereinbefore described with reference to the accompanying drawings.

A method of driving a pile into the ground and simultaneously measuring the pile shaft friction and the pile lead bearing resistance substantially as hereinbefore described with reference to the accompanying drawings.