Ajhil: /* Disturbed sample procedure */

2019-11-29T13:14:22Z

Disturbed sample procedure

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	===Disturbed sample procedure===		===Disturbed sample procedure===
	Bulk samples were collected by excavating till from the cliff face using combination of picks, geological hammers and a drill (tills were very stiff to hard). The loosened soil was collected on a tarpaulin to retain the fine fraction content. The size of the sample was dependent on the largest size fraction, following EN guidance, to ensure adequate sample quantity for sieving results to be representative of the Clay to Gravel components. Samples containing cobbles (diamicts) were greater than 30 kg and the minimum sample size was 15 kg, in accordance with BS1377:1990<ref name="BS1377 1990">		Bulk samples were collected by excavating till from the cliff face using combination of picks, geological hammers and a drill (tills were very stiff to hard). The loosened soil was collected on a tarpaulin to retain the fine fraction content. The size of the sample was dependent on the largest size fraction, following EN guidance, to ensure adequate sample quantity for sieving results to be representative of the Clay to Gravel components. Samples containing cobbles (diamicts) were greater than 30 kg and the minimum sample size was 15 kg, in accordance with BS1377:1990<ref name="BS1377 1990"></ref>.

	~~BS 1377: Part 9:1990 Methods of testing soils for civil engineering purposes. British Standards Institution. London.~~</ref>.

	===Undisturbed density rings===		===Undisturbed density rings===

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Ajhil: /* Till provenance: palynology samples */

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Till provenance: palynology samples

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__NOTOC__
{{OR/14/052}}
Various samples were taken for determination of physical properties including: grading, bulk density, natural moisture content, shear strength. Sample types included ‘disturbed’ bulk samples, and ‘undisturbed’ samples including block samples and density rings. Sample details are given in Table 1. Samples were collected in accordance with field sampling procedures described in BS1377<ref name="BS1377 1990">BS 1377: Part 9:1990 Methods of testing soils for civil engineering purposes. British Standards Institution. London.</ref> and Head (2008)<ref name="Head 2008">

HEAD, K H. 2008. Manual of Soil Laboratory Testing volume 1: Soil classification and compaction tests, 3rd edition. Whittles Publishing Ltd. 416pp.</ref>. Samples were labelled in the field and sealed to minimise moisture loss. All samples were stored in a cool box while in transit and transferred to a constant temperature (4 degrees) humidity controlled fridge prior to testing.
<center>
{| class="wikitable"
|+ Table 1    Geotechnical sample details
|- style="vertical-align:top;"
| style="background-color: #dcdcdc;" | '''Name of sample site'''
| style="background-color: #dcdcdc;" | '''Sample Number'''
| style="background-color: #dcdcdc;" | '''Type (D=disturbed, UD=Undisturbed, DR=Density Ring, PP=Panda Penetrometer)'''
| style="background-color: #dcdcdc;" | '''Description'''
| style="background-color: #dcdcdc;" | '''BNG Easting (m) (+/-5 m)'''
| style="background-color: #dcdcdc;" | '''BNG Northing (m) (+/-5 m)'''
| style="background-color: #dcdcdc;" | '''Elevation (m amsl) (+/-2 m)'''
| style="background-color: #dcdcdc;" | '''Sample Mass (field) (kg +/- 0.01 kg)'''
|- style="vertical-align:top;"
| ! scope="col" style="width: 100px;" | Cemlyn Bay
| ! scope="col" style="width: 75px;" | CB1 1/1
| ! scope="col" style="width: 100px;" | D
| ! scope="col" style="width: 150px;" | Red/Brown Till (landslide mass)
| ! scope="col" style="width: 100px;" | 232743
| ! scope="col" style="width: 100px;" | 393750
| ! scope="col" style="width: 100px;" | 6
| ! scope="col" style="width: 100px;" | ~30
|- style="vertical-align:top;"
|
|
| D
| Weakly-cemented Sand
| 232815
| 393750
| 4
| -
|- style="vertical-align:top;"
|
|
| UD
| Weakly-cemented Sand
| 232815
| 393750
| 4
| -
|- style="vertical-align:top;"
|
| CB2 1/1
| D
| Grey Till
| 232815
| 393750
| 2
| ~30
|- style="vertical-align:top;"
| Hen Borth
| HB1 1/2
| D
| Red/brown Till
| 232065
| 392984
| 6
| 23.20
|- style="vertical-align:top;"
|
| HB1 2/2
| D
| Red/brown Till
| 232065
| 392984
| 6
| 30.50
|- style="vertical-align:top;"
|
| HB2 1/2
| D
| Grey Till
| 232065
| 392984
| 3
| 23.68
|- style="vertical-align:top;"
|
|HB2 2/2
| D
| Grey Till
| 232065
| 392984
| 3
| 23.61
|- style="vertical-align:top;"
| Beaumaris
| B1 1/2
| D
| Grey Till
| 261309
| 377694
| 1
| 18.35
|- style="vertical-align:top;"
|
| B1 2/2
| D
| Grey Till
| 261309
| 377694
| 1
| 18.46
|- style="vertical-align:top;"
|
|
| DR x3
| Grey Till
| 261309
| 377694
| 1
| -
|- style="vertical-align:top;"
|
| B2 1/2
| D
| Red Till
| 261350
| 377722
| 6
| 18.00
|- style="vertical-align:top;"
|
| B2 2/2
| D
| Red Till
| 261350
| 377722
| 6
| 18.69
|- style="vertical-align:top;"
|
|
| DR x3
| Red Till
| 261350
| 377722
| 6
| -
|- style="vertical-align:top;"
| Penrhos
| PR1 1/2
| D
| Upper Grey Till/Red Till?
| 227734
| 381424
| 4
| 14.60
|- style="vertical-align:top;"
|
| PR1 2/2
| D
| Grey
| 227734
| 381424
| 4
| 18.90
|- style="vertical-align:top;"
|
| PR2 1/2
| D
| Lower Grey Till
| 227734
| 381424
| 2
| 15.00
|- style="vertical-align:top;"
|
| PR2 2/2
| D
| Lower Grey
| 227734
| 381424
| 2
| 15.00
|- style="vertical-align:top;"
| Porth Nobla — Red Till
| PN1 1/2
| D
| Red Till
| 233050
| 371119
| 2
| 18.67
|- style="vertical-align:top;"
|
| PN2 2/2
| D
| Red Till
| 233050
| 371119
| 2
| 16.40
|- style="vertical-align:top;"
| Sea Zoo — Red Till
| SZ1 1/2
| D
| Red Till
| 247048
| 364257
| 4
| 13.57
|- style="vertical-align:top;"
|
|SZ2 2/2
| D
| Red Till
| 247048
| 364257
| 4
| 18.73
|- style="vertical-align:top;"
|
| SZ3
| D
| Red Mudstone
| 247077
| 364258
| 2
| -
|- style="vertical-align:top;"
|
|
| DR x3
| Red Mudstone
| 247077
| 364258
| 2
| -
|}
</center>

==Sampling methods==

===Disturbed sample procedure===
Bulk samples were collected by excavating till from the cliff face using combination of picks, geological hammers and a drill (tills were very stiff to hard). The loosened soil was collected on a tarpaulin to retain the fine fraction content. The size of the sample was dependent on the largest size fraction, following EN guidance, to ensure adequate sample quantity for sieving results to be representative of the Clay to Gravel components. Samples containing cobbles (diamicts) were greater than 30 kg and the minimum sample size was 15 kg, in accordance with BS1377:1990<ref name="BS1377 1990">

BS 1377: Part 9:1990 Methods of testing soils for civil engineering purposes. British Standards Institution. London.</ref>.

===Undisturbed density rings===
Density rings were used to collect undisturbed samples for determination of bulk density and natural moisture content (NMC). It was not possible to obtain intact samples of till at several sites (e.g. Cemlyn Bay and Hen Borth) because the high abundance of gravel and hardness of the till makes undisturbed sampling by hand difficult. This factor results in data bias as only the ‘softer’ tills were sampled.

===Undisturbed block sampling===
The drumlin at Cemlyn Bay contains a horizontal sand body interpreted as a hydrofracture fill (Phillips and Hughes, in prep). An undisturbed block sample of the sand was gently carved by hand top down using a sharp knife (Figure 2) with a metal tin gradually lowered onto and around the column of soil to contain the sample. Great care was taken to avoid introducing discontinuities/fractures during the excavation process. The box was capped with lids on either end and was then marked with sample orientation, wrapped with cling film and taped up to minimise moisture loss.

[[Image:OR14052fig2.jpg|thumb|center|500px| '''Figure 2'''    Preparation of an undisturbed block sample of cemented sand (hydrofracture dyke) from a drumlin at Cemlyn Bay, Anglesey. A stable intact plinth is excavated by hand and box gradually lowered down encapsulating the soil sample. ]]

===Till provenance: palynology samples===
Additional samples were collected for Palynological analysis and the results are presented in Riding (2012)<ref name="Riding 2012">Riding, J B. 2012. A palynological report on the Quaternary tills of Anglesey, North Wales. ''British Geological Survey Research Report'' Internal Report IR/12/024.</ref>.

<center>
{| class="wikitable"
|+ Table 2    List of Palynology Samples
|- style="vertical-align:top;"
| style="background-color: #dcdcdc;" | '''Name of sample site'''
| style="background-color: #dcdcdc;" | '''Sample Bag Number'''
| style="background-color: #dcdcdc;" | '''Type'''
| style="background-color: #dcdcdc;" | '''BNG Easting (m)'''
| style="background-color: #dcdcdc;" | '''BNG Northing (m)'''
| style="background-color: #dcdcdc;" | '''Elevation (m amsl) +/- 2 m error'''
|- style="vertical-align:top;"
| ! scope="col" style="width: 150px;" | Sea Zoo
| ! scope="col" style="width: 75px;" | 1
| ! scope="col" style="width: 175px;" | Red Till
| ! scope="col" style="width: 90px;" | 247048
| ! scope="col" style="width: 100px;" | 364257
| ! scope="col" style="width: 90px;" | 4
|- style="vertical-align:top;"
| Beaumaris
| 2
| Grey Till
| 261309
| 377694
| 1
|- style="vertical-align:top;"
| Sea Zoo
| 3
| Red Mudstone
| 247077
| 364258
| 2
|- style="vertical-align:top;"
| Cemlyn Bay
| 4
| Weakly-cemented Sand
| 232830
| 393741
| 4
|- style="vertical-align:top;"
| Beaumaris
| 5
| Red Till
| 261350
| 377722
| 6
|- style="vertical-align:top;"
| Cemlyn Bay
| 6
| Red/Brown Till (slipped)
| 232743
| 393750
| 6
|- style="vertical-align:top;"
| Cemlyn Bay
| 7
| Grey Till
| 232815
| 393750
| 2
|- style="vertical-align:top;"
| Hen Borth
| 8
| Red/brown Till
| 232065
| 392984
| 6
|- style="vertical-align:top;"
| Hen Borth
| 9
| Grey Till
| 232065
| 392984
| 3
|- style="vertical-align:top;"
| Penrhos
| 10
| Lower Grey Till
| 227734
| 381424
| 2
|- style="vertical-align:top;"
| Porth Nobla — Red Till
| 11
| sandy Red Till
| 233050
| 371119
| 2
|}
</center>

==References==
<References/>
[[Category:OR/14/052 Physical properties of till deposits from Anglesey, north west Wales | 05]]

OR/14/052 Sample collection - Revision history

Ajhil: /* Disturbed sample procedure */

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Ajhil: /* Till provenance: palynology samples */