003 ECM_22828362_v1_Reference Document - OPW23 0189 · OPW26/0094

                                       Roughness                    Investigation Methods
                 POL                    Polished
                 RJ                     Rough                       Test Pits: These are typically undertaken with a
                 S                      Smooth                      backhoe or a tracked excavator, allowing
                 SL                     Slickened                   examination of the insitu soils. Limitations of test
                 VR                     Very Rough
                                                                    pits are the problems associated with collapse
                                                                    of the pits, disturbance and difficulty of
                       Defects                      Type            reinstatement and the consequent effects on
                 BP                    Bedding Parting              close-by structures. Care must be taken if
                 CL                    Cleavage                     construction is to be carried out near test pit
                 CO                    Contact                      locations to either properly recompact the
                 CS                    Crushed Seam                 backfill during construction or to design and
                 CZ                    Crushed Zone
                                                                    construct the structure so as not to be
                 DB                    Drilling Break
                                                                    adversely affected by poorly compacted
                 DK                    Dyke
                 DL                    Drill Lift                   backfill at the test pit location.
                 DZ                    Decomposed Zone
                 FC                    Fracture                     Hand Auger Drilling: A borehole of typical
                 FL                    Foliation                    diameter of between 50mm to 75mm advance
                 FZ                    Fracture Zone                manually operated equipment.         Premature
                 HB                    Handling Break               refusal of the hand augers can occur on a
                 IS                    Infilled Seam                variety of materials such as fill, gravel, hard
                 JT                    Joint                        clays and collapse of the borehole (typically in
                 H                     Schistosity                  non-cohesive soil).
                 SI                    Sill
                 SM                    Seam                         Continuous Spiral flight Augers: The borehole is
                 SS                    Shear Seam                   advanced using 65mm to 100mm diameter
                 SZ                    Shear Zone
                                                                    continuous spiral flight augers, which are
                 VN                    Vein
                                                                    withdrawn at intervals to allow sampling and
                 VO                    Void
                                                                    insitu testing.  Augers of up to 300mm in
                 Sampling                                           diameter are used to recover larger volumes of
                                                                    sample. Samples are returned to the surface
                 Sampling is undertaken during the fieldwork to     by the flights or may be collected after
                 allow examination of the soil or rock and to       withdrawal of the auger flights. Samples can
                 allow laboratory testing to be undertaken.         be disturbed and layers may become mixed.
                                                                    Augering below the groundwater table can be
                 Disturbed samples taken during drilling provide    less reliable than augering above the water
                 information on plasticity, grain size, colour,     table.
                 moisture content and minor constituents. Bulk
                 samples are similar but of greater volume          A Tungsten Carbide (TC) bit for auger drilling
                 required for some test procedures such as CBR      into rock can be used to indicate rock strength
                 testing.                                           and continuity by variation in drilling resistance
                                                                    and from examination of recovered rock
                 Undisturbed samples are taken by pushing a         fragments but provides only an indication of
                 thin-walled sample tube, usually 50mm              the likely rock strength. Where rock strengths
                 diameter (known as a U50), into the soil and       may have a significant impact on construction
                 collecting a sample of the soil contained in a     feasibility or costs, then further investigation by
                 relatively undisturbed state. Such samples yield   means of cored boreholes may be warranted.
                 information on structure and strength, and are
                 necessary for laboratory determination of shear    Wash Boring: The borehole is advanced by a
                 strength and compressibility.       Undisturbed    bit attached to the end of a hollow rod string,
                 sampling is generally effective only in cohesive   with water being pumped down the drill rods
                 soils.                                             and returned up the annulus of the borehole,
                                                                    carrying the drill cuttings.      Changes in
                 Details of the type and method of sampling         stratification can be determined from the
                 used are given on the attached logs.               return, together with information from “feel”
                                                                    and rate of penetration.




Document Set ID: 22828362
Version: 1, Version Date: 26/02/2024