A division of Harrison Group Environmental Ltd. Registered in England No. 1306165 Registered Office: Kimberley Street, Norwich, NR2 2RJ 5933 4031 5933 harrisongeotechnical ENGNEERING Harrison Geotechnical Engineering Kimberley Street Norwich NR2 2RJ Tel: +44 (0)1603 613111 Fax: +44 (0)1603 618120 www.harrisongroupuk.com email: [email protected]7 th July 2014 Our Ref. GN18180_SA_RG Persimmon Homes Limited (Anglia) Colville Road Works Oulton Broad Lowestoft NR33 9QS For the attention of Laura Townes Dear Sirs Pointers East, Ormesby St. Margaret – Soakaway Testing - Infiltration Test Result Summary The following investigation was carried out at the above location in accordance with our quotation dated 3 rd March 2014 and emailed instruction from the client on the 21 st May 2014. Initial background information for the site indicated superficial deposits of Diamicton (clay) and sand of the Happisburgh Glacigenic Formation, with a maximum permeability of high (sands) and a minimum permeability of low (Diamicton). 1. Site Works The purpose of the investigation was to supply soakaway test data in general accordance with BRE document 365 (Soakaway Design) at three positions beneath a proposed residential development to be incorporated as part of the surface water disposal system. We were requested to target the most permeable strata at each location. The test locations were selected in order to provide maximum coverage of the site and test all geological units within the site boundary whilst minimising crop damage within the agricultural field. The appended drawing (GN18180-DR002) illustrates the position of the test pits, which were excavated on 03/06/2014 to depths between 1.6mbgl and 1.8mbgl (metres below ground level). The trial pits were installed with a monitoring standpipe and filled with 1.0m of gravel to maintain the pit stability. Topsoil and arisings were used to backfill the pits to ground level. Water was added to each pit up to three times by a tractor towable water bowser. Falling water level readings were undertaken using manual electronic dip-meter readings by a geotechnical engineer and technician. Three fillings were achieved in trial pits TP2 and TP3, with full soakage to 25% test capacity (in line with BRE 365) achieved in each completed infilling. However, due to the slow fall in water level, only one infilling was carried out in trial pit TP1 and soakage to 25% test capacity was not achieved. Following testing, the monitoring pipes were removed. A full record of the trial pit profiles is included in the appendix with a summary provided below.
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Soakaway Testing Report 1 - Borough of Great Yarmouth
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A d i v i s io n o f Ha r r i so n G r o up E nv i ro n me n ta l L td .
Registered in England No. 1306165 Registered Office: Kimberley Street, Norwich, NR2 2RJ
Client: Persimmon Homes Limited (Anglia) Test Pit No.: TP3 Date: 03/06/2014
Trial pit filled with gravel to prevent instability in pit walls?: Yes Void Space: 30%
SOIL INFILTRATION RATE TESTIn accordance with BRE Digest 365 (1991 with amendments in 2003 and 2007)
Engineer: RGR Job Number: GN18180
Job
Location: Pointers East, Ormesby
Time to fill pit:
(minutes)03:00 Time at start of test: 10:57
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
0 200 400 600 800 1000 1200
Depth
to w
ate
r (m
bgl)
Time (seconds)
Water Level
75% full
25% full
Key:
Harrison Group, Kimberley Street, Norwich, Norfolk NR2 2RJ
Trial Pit Record
FM-Hn-R-3025-REV C
Contract No.
Location: Date:
Client: Plant: Ordnance Coordinates:
Description LegendRemarks
Depth O.D. Samples & Tests(m) Level Type Depth
Water Level Observations
Date Time WaterStrike (m)
StandingLevel (m)
Remarks:
Pit Dimensions: (L x D x W) Logged By:
KEYD
B
U
W
Disturbed Sample
Bulk Sample
Undisturbed Sample
Water Sample
Water Strike
Standing Water Level
(m) (m)
Environmental SampleES
HV
Checked By:
harrisongroup
Datum:
Results/WaterStrike
x x
Pocket PenetrometerPP
In-situ Hand Vane Test
Persimmon Homes (Anglia) Limited
1.80m
JCB 3CX
Pointers East, Ormesby StMargaret
Trial pit terminated at 1.80mbgl.1.2. Groundwater was not encountered.3. Backfill details: upon completion trial pit backfilled with
gravel to 0.80 and arisings to GL.
1.80m 0.50m
0.00
-
S. Kearney
GN18180
02/05/2014
651435E
313982N
E. Orchin
TP1
0.30
0.60
1.00
1.80
ES1
D1
D2
D3
D4
0.20
0.40
1.00
1.30
1.80
TOPSOIL (Brown gravelly CLAY. Gravel is fine to coarse subangular tosubrounded flint).
Soft grey mottled light brown slightly gravelly silty CLAY. Gravel isfine to coarse subangular flint. [HAPPISBURGH GLACIGENIC FORMATON -DIAMICTON]
Orangish brown gravelly very clayey SAND. Gravel is fine to coarsesubangular to subrounded flint. [HAPPISBURGH GLACIGENIC FORMATON -DIAMICTON]
Stiff orangish brown mottled grey slightly gravelly sandy CLAY. Gravelis fine to coarse subangular to subrounded flint. [DIAMICTON]
Trial Pit Complete at 1.80 m
Sheet 1 of 1
Trial Pit Record
FM-Hn-R-3025-REV C
Contract No.
Location: Date:
Client: Plant: Ordnance Coordinates:
Description LegendRemarks
Depth O.D. Samples & Tests(m) Level Type Depth
Water Level Observations
Date Time WaterStrike (m)
StandingLevel (m)
Remarks:
Pit Dimensions: (L x D x W) Logged By:
KEYD
B
U
W
Disturbed Sample
Bulk Sample
Undisturbed Sample
Water Sample
Water Strike
Standing Water Level
(m) (m)
Environmental SampleES
HV
Checked By:
harrisongroup
Datum:
Results/WaterStrike
x x
Pocket PenetrometerPP
In-situ Hand Vane Test
Persimmon Homes (Anglia) Limited
1.80m
JCB 3CX
Pointers East, Ormesby StMargaret
Trial pit terminated at 1.60mbgl.1.2. Groundwater was not encountered.3. Backfill details: upon completion trial pit backfilled with
gravel to 0.60 and arisings to GL.
1.60m 0.50m
0.00
-
S. Kearney
GN18180
02/06/2014
651411E
313750N
E. Orchin
TP2
0.30
0.60
1.60
ES1
D1
B1
D2
0.20
0.50
1.30
1.60
TOPSOIL (Brown slightly gravelly CLAY. Gravel is fine to coarsesubangular to subrounded flint).
Firm brown slightly sandy slightly gravelly CLAY. Gravel is fine tocoarse subangular to subrounded flint. [DIAMICTON]
Light brown mottled yellow brown slightly clayey gravelly fine tocoarse SAND. Gravel is fine to coarse subangular to subrounded flint.Occasional yellowish brown clayey pockets. Becoming very clayey withdepth.[HAPPISBURGH GLACIGENIC FORMATON - SANDS]
Trial Pit Complete at 1.60 m
Sheet 1 of 1
Trial Pit Record
FM-Hn-R-3025-REV C
Contract No.
Location: Date:
Client: Plant: Ordnance Coordinates:
Description LegendRemarks
Depth O.D. Samples & Tests(m) Level Type Depth
Water Level Observations
Date Time WaterStrike (m)
StandingLevel (m)
Remarks:
Pit Dimensions: (L x D x W) Logged By:
KEYD
B
U
W
Disturbed Sample
Bulk Sample
Undisturbed Sample
Water Sample
Water Strike
Standing Water Level
(m) (m)
Environmental SampleES
HV
Checked By:
harrisongroup
Datum:
Results/WaterStrike
x x
Pocket PenetrometerPP
In-situ Hand Vane Test
Persimmon Homes (Anglia) Limited
1.80m
JCB 3CX
Pointers East, Ormesby StMargaret
Trial pit terminated at 1.70mbgl.1.2. Groundwater was not encountered.3. Backfill details: upon completion trial pit backfilled with
gravel to 0.70 and arisings to GL.
1.70m 0.50m
0.00
-
S. Kearney
GN18180
02/07/2014
651214E
313654N
E. Orchin
TP3
0.40
0.70
1.70
ES1
B1
B2
D1
0.20
0.70
1.20
1.70
TOPSOIL (Brown slightly sandy gravelly CLAY. Gravel is fine to coarsesubangular to subrounded flint).
Yellowish brown clayey gravelly fine to coarse SAND. Gravel is fine tocoarse subangular to subrounded flint. [HAPPISBURGH GLACIGENICFORMATON - SANDS]
Yellowish brown slightly silty very gravelly fine to coarse SAND.Gravel is fine to coarse subangular to subrounded flint. [HAPPISBURGHGLACIGENIC FORMATON - SANDS]