9.7 Workplace transport practices

Good working practices should be adopted to assist in the mitigation of workplace transport risk during earthmoving operations.

Consideration should be given to both the workforce and the public.

Information on routes and parking or delivery points should be provided to all drivers, operators, delivery drivers and visitors during a site induction and should be updated from a manned and controlled site entrance.

Pedestrian and cycle routes should be kept separate from vehicle routes and working areas. Further division between heavy earthmoving plant and light wheeled traffic should be considered where practicable.

Supervisors should aim to work from vehicles and use radio to communicate with plant operators. Surveying and earthworks testing should be kept separate from earthmoving operations. Movement of site personnel, including visitors, should be preferably by vehicles and walking should be designed out of the works where reasonably practical to do so.

Welfare and messing provisions should be managed to minimize the need for pedestrian movements. Personnel transport from remote locations should be provided if appropriate.

Fuel distribution and emergency maintenance carried out on site should be undertaken in demarcated areas.

The need for banksmen should be carefully assessed and they should be deployed sparingly. Signalling to operators as to where to load or tip may often be done from their cabs by the excavator operator or by the operator of the machine spreading the tipped loads or remotely by radio. End tipping over unprotected faces should be avoided by the use of an attendant dozer.

Haul roads should be of good construction, well drained, properly maintained and demarcated. Speed limits on haul roads should be appropriate to the traffic using them and enforced by traffic calming measures such as changing layout, chicanes, speed bumps, hanging gantries, traffic lights and proactive enforcement by supervisory staff.

Signing, traffic control measures and lighting at crossing points should all reflect current highway practice (see DMRB Volume 8 [59]).

The wearing of hi-visibility clothing by personnel and the use of flashing beacons on vehicles should be standard practice.

9.8 Material delivery

Delivery of materials to site should be managed by the contractor. In planning deliveries the contractor should consider; the physical constraints imposed by the site and access routes, the quantities of material involved, off-loading provision, security and protection of goods, and opportunities to avoid double handling.

Consideration should also be given to:

  • a) the packaging materials used so as to minimize waste generation and disposal costs;
  • b) the time and frequency of delivery, arrangements for being received on site, restrictions on roads and areas outside the site, e.g. deliveries past schools.;
  • c) the induction process for the driver, security clearances or other requirements that the driver has to have to enter the site (in addition to those required to drive the vehicle or transport specific goods);
  • d) information for the driver such as site entrances and exits, site plan and hazards (cranes lifting loads/machine movements), delivery areas, turning areas, traffic restrictions, and means of escort if required;
  • e) contingency plans;
  • f) a plan/safe system of work for the material storing requirements, e.g. stacking, flat on floor, in a covered building, with a view as to how this might affect their subsequent removal by others.

Storage areas should be located in one place with materials being distributed out in smaller quantities as required.

9.9 Control and monitoring of earthworks

9.9.1 Inspection of excavations

Excavations for cuttings and foundations should be inspected to confirm the design assumptions were appropriate.

9.9.2 Stability and settlement monitoring

Monitoring of earthworks stability and settlement should be undertaken and recorded. The monitoring regime should be designed and implemented to ensure that:

  • a) adverse ground movement is detected during and post construction;
  • b) resultant damage to structures can be minimized; and
  • c) the design assumptions have been satisfied.

The information from monitoring should be used to initiate and control works to prevent damage where necessary.

9.9.3 Observational methods

The observational method may be adopted for the control and monitoring of earthworks (e.g. its principles are routinely used on earthworks projects for construction of embankments over soft ground, or excavation adjacent to sensitive structures). It should be undertaken in accordance with the principles set out in CIRIA R185 [16]


The observational method in ground engineering is a continuous, managed, integrated process of design, construction control, monitoring and review which enables previously defined modifications to be incorporated during or after construction as appropriate. All these aspects have to be demonstrably robust. The objective is to achieve greater overall economy without compromising safety. The method's origins are found in the development of "modern" soil mechanics theories in the late 1940s, when an integrated process for predicting, monitoring, reviewing and modifying designs evolved. In the 1990s there was a noticeable increase in its use, and extension of its principles. The OM has been recognized as a design method in design codes such as BS EN 1997-1:2004.

9.9.4 Earthworks control testing

The minimum amount of control testing should be given in the specification for earthworks in conformity with Clause 8. However, the contractor may choose to do more testing to ensure the specification is met, and to assess the sensitivity of materials for handling purposes.

Even when using an end product specification, the contractor should develop a methodology to control the works in order to ensure that the final end product will be achieved.

NOTE This can be particularly relevant for end product earthworks for developers where the contractor can effectively become the earthworks designer to meet a limited set of criteria.

9.10 Embankments

The method of embankment construction should normally be determined by the earthworks contractor. The compaction plant should be chosen to suit the nature of the fill and the scale of the operation, and reference should be made to SHW [1] Table 6/4.

NOTE Guidance on the formation of embankments are provided in SHW [1] Clause 612

9.11 Excavations

The method of excavation should normally be determined by the earthworks contractor based on the scale of the excavation, materials to be removed and availability of plant. Temporary drainage during construction should be installed to minimize deterioration of fill material and sub-grade (see 7.5).

NOTE 1 Current practice for mechanical excavation is to use backacters and face shovels.

Within the vicinity of buried services, hand-digging to locate the services should be undertaken.

Where buried structures or rock are to be removed, more specialist techniques should be specified (see 9.12).

NOTE 2 Guidance on the formation of cuttings and cutting slopes, and excavation for foundations are provided in SHW [1] Clauses 603 and 604, respectively.

9.12 Excavation in rock

9.12.1 General

The contractor should determine the ease of excavation in rock from interrelationship between a number of physical parameters, the most important of which include the intact rock strength, degree of weathering and the nature and spatial distribution of discontinuities within the rock mass.

NOTE 1 Very strong, unweathered, weakly discontinuous rock masses (e.g. coarse crystalline igneous and metamorphic rocks, or massive sandstones and limestones) require a significant amount of inputted energy to break them and enable their excavation. Weaker, highly fractured or weathered rock masses can be excavated with relative ease, similar to that of a soil.

There is a range of methods which may be considered for breaking out rock taking into account the noise, dust and vibration generated, the geotechnical properties of the rock mass, the amount of rock to be excavated and the environment in which the work is to be undertaken; these include:

  • drill and blast (see BS 5607 and BS EN 791);
  • mechanical and chemical bursting techniques;
  • ripping;
  • backacters and face shovels;
  • impact hammers (see BS EN 12111); and
  • roadheaders (see BS EN 12111).

Specialist advice on the most appropriate method to use for a given project with unfavourable rock mass characteristics and environmental scenario should be sought from an experienced earthworks contractor.

NOTE 2 Further guidance can be found in Pettifer and Fookes [60], Fookes and Sweeney [61], Caterpillar Performance Handbook [62].

9.12.2 Special considerations for blasting

Careful consideration should be given to the consequences of blasting where:

  • a) the site is in close proximity to structures or populated areas;
  • b) the site is adjacent to transport corridors;
  • c) the site adjoins public buildings such as schools or hospitals;
  • d) unacceptable levels of noise, fume or vibration would be generated by the blasting;
  • e) damage might be caused to excavation supports or the surrounding ground, rendering the design unsafe; or
  • f) excessive fracturing of the resultant material for fill purposes.

Where a structure(s) might be influenced by ground borne vibrations derived from blasting operations, a full photographic structural survey should be conducted by an appropriately qualified person prior to commencing excavation.

When moving rock broken out using explosives, care should be taken to ensure no undetonated explosives remain in the material to be excavated.

NOTE Further guidance can be found in SHW [1] Clause 607.

9.12.3 Control of overbreak

In order to minimize overbreak, specialist techniques such as rock sawing, pre-split blasting, etc. should be employed. Specialist contractors should be consulted on the most appropriate method to use for the situation.

NOTE Overbreak frequently occurs within rock masses having unfavourable spatial distribution of the discontinuities, particularly within confined excavations, depending on the excavation method employed.

This can lead to destabilization by undermining and loosening of the rock as well as the generation of excess spoil and the need for imported materials and/or concrete to make good formations, etc.