THE LYTTELTON HARBOR WORKS.

Press, Volume XI, Issue 1338, 20 February 1867, Page 2

THE LYTTELTON HARBOR WORKS.

TO THE EDITOR OF THE " PBESS." 1 Sib, —In continuation of the subject of my I former letter, I now como to that part of tin | enquiry relative to foundations, and in doui» | so it would seem almost a work of supcreroje- I tiou to attempt to show that tho author of a 1 work (intended for the information of the I million) should bo unacquainted with the 1 practical application of his own text— 1 " Foundations " —yet so it would seem ; tho | case of Lyttelton harbor being an illustra- § tion of the furore indulged in by a certain 1 section of the profession for book making, | when the application of tho principles so f learnedly discussed is foreign to their own f practice. The project to enclose and rock!;? a sea-beach by means of piles, to be '•! filled in with loose material, and having „ \ perpendicular face of eighty feet to a strong c tideway and a non-cohesive deposit of mud,h I a Bcheme so unique that a parallel might hi j sought for in vain. In "Stovenson's Civil 1 Engineering of North America" such con- 1 struction is recommended on tho shores of I laVes, and in other situations whero the ripp], f of the water or a sudden squall is tho only | occasion upon which tho strength of tlio pier f or jetty is tried, and whero a strong adhesive 1 mud of almost unascertained depth (being a I part of that remarkable deposit known as "tho j boulder clay or northern drift, derived origi< I nally from morains or detritus brought down by 1 glaciers during that period of the world* ! history,) offers holding-ground suited to tha j undertaking. The failuro of work in such a | situation as Lyttelton is evidently due in tha jj first place to the want of this retentive sub* 1 stratum, as well as the impossibility of driving 1 (to a practicable depth) piles into a hiai I burnt rocky bottom. In the second place, tha i possession of these desiderata would be quit. 1 insufficient I imagine to secure the permanency i of the work, ns the project of filling in th» j inclined plane, commencing at high-water mark j and falling precipitously to the foot of the piles f eighty feet below the same level, with looserook I maintaining a constant pressure seawards, and | resisted only by loose mud and tidal wat.r,inust | bo futile for many reasons—thus, water in a j tide-way when disturbed acts with a percussivo | force sufficient to shake and deflect any ! wooden construction —thus giving motion to * the filling in and causing a settlement of the r stone, which acts as a wedge in forcing out tho > wall. This action would be greatly aidoii by j tho bumping of shipping in rough weather ' aggravating tho evil. Agaiu.it was proposed to run heavily laden trucks over tho top of this sea-wall, thus introducing another elemeat oi weakness by imparting a vibration to tho «traC" turo which would have greatly addod to the . chance of its ultimate destruction; a caw i often illustrated on railway embankments having a piled timber breast similarly filled in. | In the third place, all kindred undertakuigiJ ' heretofore constructed in the United Ktngdoffl - t have been totally opposed in principle an.> : material used to the present project, and t having answered the end in view, condemn tns j temporary expedient resorted to in this caM; ' Another important consideration is connected ; with tho value or cost of the land to c* ; reclaimed, supposing the project feasible, wkiCu its present forlorn appearance would seem « contradict. This is a maftor of primary f»- . port, and should have been well consiaersjt, ; as all engineering questions must eventually resolve themselves into financial particularly when the money is borro*W aud the interest paid for its usebecWWj* * permanent charge on the revenue of j" • province. To arrive at a reliable conclns« B : , on this point, it would bo necessary tain the cost of permanently enclosing thuj*T tion of beach, which, judging by works slreaoj ( executed in England, would be beyond^ tion too expensive and the height of k»V* j attempt, particularly when the desirfid «cej modation could be otherwise aud c.iesp. obtained. . , rtS * The screw-pile jetty is another fatalw»»»r of attempting to realise an idea mthcMw necessary investigation enabling a «a« lß i^' a , become to whether screw-piles or «»tfi" , s j!. ■ at all should have been used. The r*u»» f'iis case is even more disastrous and !' in proportion, than tho-ideal sea-wall. J* * wo find a vc. y useful invention, . ;to speak, and' abused by being put iv | tion where it is of no moro s9^r'x,ulii, ( "* i the roughest pile over driven. M ,';__!_ f invaluable invention was never moro a* o f applied than in the present histance,* ~ tho weight of tho flange prows .»uIMW' iiiiJ the bottom without mechanical »«• ; a littlo pi-.vious exploration woaia . ♦ m-ulo knovi-u the futility of the *™ fa j Throughout tho progress of tlio "° J contractor brings to ti-.e notice ot tlia *«» . the various indications of failure, w fc , entirely disregarded—a state of thing* , ing ill under any circumstances, anai havo called for tho opinion oi oUM* QB long beforo £00,000 of borrowed cap««"

""""""T _■ in the mud of lyttelton harbor n f ?lTr. minion of the projector, and t. mm t» p . 0 f a profession whose call- « '/C%>rio..W working for the »* fin iin every country and under every public «5°? d anocess which has given all c jime. :-:' c ~ ration, but « nlW . r *S,£ 0 f the works already described TheP S so signal a failnre.it would J,rin -«Kiole that a proposition should be BW r?_Tnend a further sum in constructing jostle ten"- o f tl) . ptinlo character, but another sea- g of o . ltsi j e the preifiih_ re ?. te Tli( T a ,fcmpt must be as un.ucce.sM nt wors- jhe former one—the printhe construction being the weak trespass further on your 1 to ventilate this portion of the inquiry, T will therefore, in my next letter, pro- _ a step father wite the general question. CEe I remain, yours obediently, 11. B. HUDDLESTON, CE. Avonside, February 13, 1867.