m60 ashton moss plot 2000 enabling works (terraconsult data sheets, 2011)

8/12/2019 M60 Ashton Moss Plot 2000 Enabling Works (TerraConsult Data Sheets, 2011)

1/6

Project Data Sheet Geotechnics (Retaining Wall)

Project Barrow Docks, Cumbria Area 8 Ha

Client Associated British Ports & ODE Ltd Year 2009/10

This project was carried out in two phases. Phase 1was carried out for Associated British Ports (ABP)and comprised preliminary analysis of the stabilityof the dock walls in three separate areas of thedocks to determine whether they will be stable whensubjected to the very high loads from the crane lifts(two cranes acting in tandem carrying 600 t eachand travelling up to the dock wall). This work is to

enable off-loading, storage and fabrication of 5 mdiameter steel monopiles and off shore platforms fornew wind farms in the Irish Sea. After fabrication theunits will subsequently be loaded back onto barges.

The assessment was based on the original Victorianconstruction drawings and site investigation datafrom other areas of the docks. This phase of workconcluded that the dock walls were likely to bestable but further assessment would be required toconfirm this and to determine whether any remedialworks would be required. This further phase of workwould require to be based on new site specific site

investigation data.

Phase 2 of the work was carried out for OffshoreDesign Engineering Ltd (ODE) who are thedesigners and project managers for the offshoreworks. TerraConsult assessed the stability of onedock wall when it is subjected to the very high loads(up to 1100 t) from a self propelled modulartransporter carrying a newly-constructed sub-stationplatform travelling up to the dock wall. The workinvolved site investigation to augment the limiteddata provided by ABP and further analyses werecarried out to check stability for the areas associatedwith off-loading, storage and fabrication of thematerials for the construction of the sub-stationplatform. Analysis involved assessment of a numberof complex loading scenarios all with a range of veryhigh localized loads.

Reference:Thomas TsantikosOffshore Design Engineering Ltd10-14 Princeton Mews167-169 London RoadKingston-Upon-Thames

Surrey KT2 6PTTelephone: 02085 412 063


2/6

Project Data Sheet Geotechnics (Slope Stability)

Project Fletcher Bank Quarry Area 48 ha

Client Marshalls Plc Year 2008 - 2010

Fletcher Bank is a working quarry located just off theA56 Manchester Road in Ramsbottom, Lancashire. In2008 TerraConsult were commissioned to carry outreserve calculations for a proposed extension to theexisting quarry area. To support this work, TerraConsultprocured and project managed a programme of rotarydrilling across the extension area, utilising both openhole and coring techniques. The key objectives were

to determine the thickness of the main sandstone unitsand to assess rock quality.

Alongside the investigation works, a detailed geologicalsurvey of the quarry face was undertaken through acombination of direct face logging, but mainly byremote survey techniques. Direct face logging hassignificant safety risks due the need to approach theworking quarry face. These safety hazards do not applywhen undertaking the remote survey method.

The collected survey data was utilised alongside theinvestigation information to model the surface of each

quarry unit, thus allowing the available reserves in theextension to be calculated.

During 2009/10 TerraConsult also carried out a stabilityassessment for a waste silt lagoon located at thesouthern end of the quarry. The silt, originally sourcedfrom the on-site washing facility, is retained within in-situ rock and two engineered buttresses. To supportthe stability assessment, intrusive investigation workswere carried out through rotary drilling and ConePenetration Testing (CPT). The investigation data wasused to derive appropriate material parameters whichwere then utilised in the analysis. The stability

assessment was carried out in accordance with theEurocode 7 (BS EN 1997-1:2004) design methodology,utilising the slope stability analysis programmeXSTABL.

Reference:Brian MorrisQuarry ManagerMarshalls PlcFletcher Bank QuarryManchester RoadRamsbottomLancashire

BL0 0DD


3/6

Project Data Sheet Geotechnics (Earthworks)

Project Ashton Moss Plot 2000 Enabling Works Value 5M plus

Period 2 years plus

Client P Casey Civil Engineering Ltd Year 2000-2003

This challenging project provided the roadworks forthe Ashton Northern Bypass and the EnablingWorks for Plot 2000 of the Ashton MossDevelopment, a 12 Hectare commercial and leisuredevelopment site on Junction 23 of the M60. Itcomprises part of the 64 Ha site designed andsupervised by TerraConsult.

Peat and underlying alluvial clays had to beexcavated and replaced with engineered fillcomprising compacted selected importedConstruction, Demolition and Excavation Waste(CDEW). Control of the quality of the fill, in terms ofboth the chemical contamination and thegeotechnical properties was made more difficult bya tight timescale which required constructionthrough two winters to meet programme.

To minimise the double handling of large quantitiesof surcharge and the timescale of normal surchargesolutions several options were adopted. The plots

where the earliest hand-over dates were situatedused vertical band drains beneath surcharges butall later fill used horizontal geosynthetic drainagelayers at one metre centres to radically reducesurcharge heights and periods. Monitoringdemonstrated adequate settlement generally withinfour weeks.

The work continues in 2005 and beyond on anearby area where the excavated peat and furtherimported CDEW capping are being engineered toprovide a golf course, playing fields and allotments.

This work was carried out as the Designer under anICE Design and Construct Contract with the MainContractor, P Casey (Civil Engineering) Ltd., for

AMEC Development Ltd and Stayley DevelopmentLtd.

Reference:Peter CaseyP Casey Civil Engineering LtdRydings Lane,Rochdale,Lancashire,OL12 9PS

Tel: 01706 341121


4/6

Project Data Sheet Geotechnics (Slope Stability)

Project St Marys Caravan Park, Prestatyn Area 5.2 Ha

Client Royal Bank of Scotland Year 2008 - 2010

TerraConsult was commissioned by West Register(Realisations) Ltd on behalf of RBS to carry out aPhase 1 and preliminary Phase 2 site investigation ata former caravan park in Prestatyn. The purpose ofthe investigation was to provide general informationon the site ground conditions and, more specifically,to carry out a preliminary assessment of the stabilityof a gabion wall located at the southern end of the

site. The information was required to support theredevelopment of the site, with the proposed enduse again being a caravan park.

Following a detailed desk study and walkover,intrusive investigation works were carried out at thesite through both trial pitting and a series of dynamicwindow sample holes. These showed the site to beunderlain by a considerable thickness of glacial till(typically firm to stiff clay). They also indicated thatthe site had been subject to a significant cut/fillexercise in order to create benches for locatingcaravans. Alongside the investigation works, a

condition inspection of a 150 m long gabion wallwas carried out, which in some places extended toa height of > 7m. Above the walls crest level theglacial till had been trimmed back, in some areasattaining a gradient of 1 in 1.5.

Based on the findings of the site works, anassessment of the gabion wall was undertaken todetermine the acceptability of the design. Theassessment included stability checks, carried outprincipally using the finite difference programmeFLAC/SLOPE. The assessment indicated that thedesign of the gabion wall was unacceptable withinstability of the wall likely to occur in the future. Anumber of remedial options were subsequentlyprovided, with the use of soil nails the preferred option.

Alongside the geotechnical aspects, a preliminaryassessment of ground contamination wasundertaken in accordance with BS 10175: 2001Investigation of Potentially Contaminated Sites Code of Practice. The assessment highlighted theneed for full radon protection measures in any newbuildings constructed on site.

Reference:


5/6

Project Data Sheet Geotechnical (Rock Slope Stability)

Project Llanddulas Quarry Area N/A

Client Waste Recycling Group Year 2003

Llanddulas Quarry is a disused quarry adjacent tothe A55 North Wales Trunk Road. Consideration isbeing given to its long term re-use and it wasrecognised that there might be constraints todevelopment caused by the steep quarry walls.These appear generally stable but to enable initialplanning layouts to be evaluated the constraintsfrom instability and potential rockfall needed to be

defined.

The planning consultants AXIS PED Ltd requested astability survey with treatment options with theirspatial constraints plus indicative treatment costs.

TerraConsult used their past experience ofgeotechnical survey in mines and quarries to safelymap and survey the faces. They used advancedremote face profiling survey techniques andtraditional geotechnical measurements of the dipand strike measurement of joints in the rocks. Thedata obtained was used with a series of computer

software packages for analysis and to provide theparameters and required guidance.

Such work is relatively inexpensive and reduces riskwhich in the past would have required roped accesson the faces which would have been relatively costlyin risk, time and monetary terms.

Reference:Nick RobertsAXIS PED Ltd

Well House BarnsChester RoadBrettonChesterCH4 0DHTel: 0844 8700 007


6/6

Project Data Sheet Geotechnical Expert Witness

Project M60 J23 Cutting Slope Failure Value 200,000

Client Highways Agency Year 2001 - 2005

Following a slip in the cutting of the M60 motorwaynear Junction 23, Ashton under Lyne, the Highways

Agency asked Alan Binns of TerraConsult tocomplete the investigation into the mechanisms andcauses of the failure. During construction on theadjacent site, the contractor had surcharged theground to reduce settlement in the peat andalluvium which existed below their filled site.

The slippage moved the surcharge mound and itssupporting subgrade en bloc some six or sevenmetres towards the highway.

Extensive site investigation and laboratory testingtogether with analyses was carried out and lead toconclusions about the mechanisms of failure.Conventional light percussive boreholes werecombined with CPT testing on site together withsubstantial trial trenches to examine the slippedmaterials. Health and safety issues of trenchingthrough a failed slope on the motorway hard

shoulder had to be addressed. Laboratory testingincluded effective stress triaxial compression teststogether with the results of large shear box tests.

It was established that slippage of the surchargemound along weak clay layers at depth spread tothe highway cutting slopes. High porewaterpressures were induced in the soft clay and spreadto the highway cutting slope causing slippage alongplanar surfaces.

Reference:Mr C DuffellHighways Agency Sunley Tower,Piccadilly Plaza,Manchester,M1 4BETel: 0161 930 5660

m60 ashton moss plot 2000 enabling works (terraconsult data sheets, 2011)

Documents