Deep Trench Excavation & Shoring Method with Dewatering and ITP

More than a static template

Unlike a downloadable Word or PDF template, this method statement is an AI-assisted editable starting point connected directly to a matching Inspection and Test Plan. Every section is structured, project-adaptable, and ready to export.

AI-assisted drafting — Customize every section with AI for your specific project scope.
Linked ITP — A matching inspection and test plan is generated alongside the method statement.
Multiple export formats — Download as a formatted PDF or editable Excel spreadsheet.
Editable starting point, not a final document — Review, verify, and adjust all content against your project requirements before use.

Static template vs. Quollnet workflow

Feature	Static template	Quollnet
Project-specific content	Manual fill-in required	AI-assisted customization
Linked ITP	Separate document, no link	Matching ITP included
Export formats	Usually PDF only	PDF and Excel
Structured sections	Free-form layout	13 standardized sections
Saved to your account	Local file only	Cloud-saved, reusable
Content accuracy	You verify everything	AI-assisted, you still verify
Cost	Often free but time-intensive	Free to customize and download

What you can customize

When you save this method statement to your account, every section becomes editable. The following 13 sections are included:

Scope — Defines the activity and its boundaries.
References — Standards, specifications, and drawings.
Responsibilities — Roles and accountabilities.
Resources — Labour, plant, and equipment summary.
Materials — Materials and compliance requirements.
Equipment — Tools and equipment details.
Prerequisites — Hold points and pre-conditions.
Method sequence — Step-by-step construction sequence.
Safety controls — HSE risk controls and PPE.
Environmental controls — Environmental mitigation measures.
QA/QC — Quality inspection and test requirements.
ITP — Inspection and Test Plan table (has its own page).
Attachments — Referenced drawings and documentation.

Why this method statement is used

This method statement is used to define and communicate the approved procedure for carrying out method statement: deep trench excavation and shoring installation for stormwater mainlines on site. It ensures the work is planned in advance, the correct resources and controls are in place, and all personnel understand responsibilities, sequence, quality requirements, and safety controls before work begins. It aligns site execution with the documented scope and acceptance expectations.

Who uses this method statement

This method statement is used by contractors, site supervisors, project engineers, QA/QC engineers, HSE officers, consultants, and client representatives. It serves as a shared reference for planning, execution, supervision, inspection, and approval of the activity on site.

When it is prepared and submitted

The method statement is prepared before the work activity starts and submitted as part of the pre-construction documentation package for review and approval.

Who reviews or approves it

The method statement is usually submitted to the client representative, consultant, resident engineer, or project management consultant for review and approval before the work commences.

Important approval note

This method statement is an AI-assisted editable starting point, not a pre-approved document. Before use on any project, all content must be reviewed and approved by the relevant parties (superintendent, principal contractor, or client representative) in accordance with your contract and project quality plan.

For example: if your specification requires a departure from a referenced standard, that departure must be documented and approved separately — this method statement will not capture that automatically. Always verify against your applicable drawings, specifications, and regulatory requirements.

Method statement content

Scope

Overview

This method statement details the execution of deep trench excavation and temporary shoring for installation of stormwater mainlines, with optional use of slide-rail systems or trench boxes. It addresses utility locating and protection, groundwater control, soil classification, temporary works design and monitoring, trench access/egress, trench backfilling within pipe zone, and associated QA/QC and HSE controls.

Limits of Work

Trench lengths as per IFC drawings [Verify per project specifications].
Depths typically 3.0–7.0 m; trench width as required for pipe OD, shoring, and safe working clearance [Verify per project specifications].
Ground conditions per geotechnical report (cohesive/non-cohesive soils; groundwater expected near/above trench invert in sections).

Key Outputs

Verified service clearances and pothole records.
Installed and monitored dewatering system with compliant discharge.
Installed temporary shoring (slide-rail or trench box) to maintain stable trench.
Safe access ladders within 7.5 m of all workers and extending ≥1.0 m above surface.
Verified trench dimensions, levels, and compliance records.

Interfaces/Exclusions

Interface with pipe-laying crews and manhole construction.
Traffic management by approved plan.
Utility isolation/permits by asset owners as needed.

References

Document Type	Reference / Number	Notes
Standard	EN 1997-1	Temporary works design principles for excavations and support [Verify per project specifications].
Standard	EN 13331 (Parts 1 & 2) [or equivalent national standard]	For trench boxes and slide-rail components [Verify per project specifications].
Standard	BS 6031	Excavation, stability, backfill guidance.
Guidance	CIRIA C750	Wellpoint/deep well design and monitoring.
ASTM	ASTM D2487	For trench stability and dewatering design inputs.
ASTM	ASTM D698 / ASTM D1557 (or BS 1377)	Basis for field density acceptance.
ASTM	ASTM D6938	Alternative sand-cone ASTM D1556.
Regulation/Standard	OSHA 29 CFR 1926 Subpart P [or local equivalent — verify]	Trench protection, access/egress, inspections [Verify per project HSE plan and local regulations].
ISO	ISO 9906	For dewatering pump performance verification (as applicable).
ISO	ISO 45001 / ISO 14001	Framework for HSE controls [Verify per project].

Responsibilities

Role	Responsibility	Name / Party
Project Manager	Project Manager	Contractor
TWC	Temporary Works Coordinator (TWC)	Contractor
Designer	Temporary Works Designer / Shoring Supplier Engineer	Specialist
HSE	HSE Manager / HSE Officer	Contractor
Surveyor	Surveyor	Contractor
Coordinator	Utility Coordinator	Contractor
Site Engineer	Site Engineer / Foreman	Contractor
QA/QC	QA/QC Engineer	Contractor
AP/Crane Supv/Banksman	Lifting Appointed Person / Crane Supervisor / Banksman	Contractor

Resources

Resource Type	Description	Quantity	Remarks
Labour	Foreman, Site Engineer, Excavator Operator(s), Pipe Layer(s) interface, Skilled Workers, Banksman, Pump Technician, HSE Officer, Surveyor, QA/QC Technician	As required
Permits	Excavation permit, Hot work (if any), Dewatering/discharge permit, Traffic management approval, Utility crossing permits

Materials

Material	Specification / Grade	Quantity	Remarks
High-strength steel		As per design

Equipment

Equipment	Capacity / Type	Quantity	Inspection Required
		As required	Yes
			Yes
			Yes
			Yes
			Yes
			Yes
			Yes

Prerequisites

Permits and Approvals

Approved excavation permit, traffic management plan, and dewatering/discharge permit.
Temporary Works Design (TWD) for shoring approved by the Engineer; category and independent check defined.
Utility clearances from all asset owners; isolation/shutdown arranged where required.

Information and Surveys

Geotechnical data reviewed (soil stratification, permeability, shear strength, groundwater levels).
Precondition survey of adjacent structures/pavements; baseline settlement/deflection markers installed where needed.
Service locating completed using GPR/EML and potholing to confirm depths and alignments at all crossings.
Set-out control established and protected; benchmarks verified.

Method Controls and Planning

Risk assessment and method briefed to crew (toolbox talks) including rescue plan.
Lifting plans for shoring components approved; plant access routes verified for bearing capacity.
Dewatering design (wellpoint spacing, pump sizing, discharge route, monitoring) approved; contingency/standby pumps arranged.
Materials and equipment inspected; calibration certificates current.
Weather and flood risk reviewed; stop-work criteria defined for heavy rainfall or water inflow beyond pump capacity.
Waste management and sediment control measures installed.

Hold/Witness Points

H1: Utility clearance and pothole verification before excavation.
H2: Shoring delivery inspection and TWC pre-use inspection.
W1: Dewatering commissioning and drawdown trial.
H3: First bay excavation and shoring installation check (pattern approval).

Method Sequence

Step	Activity	Description	Responsibility	Inspection / Hold Point
1	Site establishment and traffic control	Install traffic management, barriers, signage, lighting per approved plan; establish exclusion zones and plant routes.	Site Engineer/Foreman	HSE walkdown
2	Utility locating and potholing	GPR/EML scanning along the alignment; hand or vacuum excavate trial pits at crossings to positively locate services and set protective coverings/slinging points.	Utility Coordinator/Foreman	Hold point H1
3	Dewatering installation	Install wellpoints at 1.0–1.5 m spacing or deep wells as designed; header pipe with isolation valves; discharge to settlement tanks and approved outfall with oil booms.	Dewatering Subcontractor	ITP witnessing W1
4	Initial excavation (pilot bay)	Excavate first bay to ~0.5–1.0 m depth; trim to shoring footprint; maintain spoil 0.6–1.0 m away from edge with toe boards.	Foreman/Operator	Engineer/TWC check
5	Shoring installation – slide-rail (option)	Place corner posts and insert panels progressively using dig-and-push method; install spreaders at designed elevations; maintain panel embedment below formation.	Shoring Crew/TWC	Hold point H2/H3
6	Shoring installation – trench box (option)	Lower box using crane/excavator; excavate ahead, advance box progressively keeping shield close to face; set spreaders to maintain width.	Shoring Crew/Banksman	TWC check
7	Progressive excavation to formation	Excavate in stages (≤1.0 m lifts) with concurrent shoring advancement; maintain access ladders within 7.5 m; manage groundwater inflow.	Foreman/Operator	Shift inspections
8	Access/egress and edge protection	Install secured ladders extending ≥1.0 m above ground; edge barriers 1.1 m; ladder spacing ≤7.5 m along trench.	Foreman/HSE	HSE inspection
9	Utility crossings	At crossings, hand-dig within 0.5 m of service; provide bridging/protection mats; reduce excavator forces; install additional local shoring as required.	Foreman/Utility Coordinator	Engineer witness
10	Formation verification	Survey invert and line using laser/total station; confirm trench width and benching (if any).	Surveyor/QA-QC	ITP hold
11	Pipe zone bedding (if in scope)	Place bedding layer 100–150 mm; compact with vibratory plate avoiding shoring contact; verify level.	Foreman/QA-QC	ITP witness
12	Monitoring during works	Daily shoring inspection by competent person; check deflection, spreader loads (visual/strain gauges if specified), ground movement markers, and water levels.	TWC/Engineer	Daily
13	Backfilling around pipe zone (after pipe installation)	Place sidefill and initial backfill in ≤200–300 mm lifts; compact with suitable equipment avoiding pipe flotation/box contact.	Foreman/QA-QC	ITP witness
14	Shoring extraction	Extract slide-rails/panels or trench box incrementally while backfilling to avoid voids; ensure no suction on pipe or bedding.	Shoring Crew/Banksman	TWC oversight
15	Demobilization and reinstatement (temporary)	Remove dewatering after rebound monitoring; cap wells; remove temporary works; tidy site; maintain temporary surface.	Foreman/Dewatering Subcontractor	Final inspection

Health & Safety Controls

Hazard Controls (Task-Specific)

Hazard: Undetected underground utilities strike (electric, gas, fiber)
Consequence: Electrocution, explosion, service outage
Engineering/Procedural Control: GPR/EML survey, potholing; no mechanical excavation within 1 m until service proven; insulated tools near LV; asset owner permits and supervision for critical crossings; machine slew/height restrictors near overheads.
PPE: Dielectric gloves (as required), arc-rated clothing near electrical, eye/face protection, safety boots, HV vest
Collective Measure: Physical barriers and marker tapes; temporary protective mats/bridging over services
Inspection/Permit/Supervision: Excavation PTW; utility crossing permit; competent person supervision; daily service location briefings [Verify per project HSE plan and local regulations]
Hazard: Trench collapse/shoring failure
Consequence: Burial/asphyxiation, serious injury/fatality
Engineering/Procedural Control: TWD-compliant slide-rail/trench box; pre-use inspection; daily competent person inspection; no entry outside protection; exclusion zone; maintain pump capacity; adhere to TARP triggers
PPE: Helmets with chin strap, gloves, steel-toe boots, eye protection
Collective Measure: Engineered shoring, edge barriers, spotter control
Inspection/Permit/Supervision: TWC inspections before use and after any event (rainfall, impact); recorded daily
Hazard: Plant-lifting incidents during shoring placement
Consequence: Crushing, struck-by, component drop
Engineering/Procedural Control: Appointed Person lift plan; certified lifting accessories; tag lines; defined exclusion zone; no personnel in trench during suspended loads
PPE: Helmet, gloves, boots, eye protection, high-vis
Collective Measure: Barriers and banksman control; radio comms
Inspection/Permit/Supervision: Pre-lift checks; LOLER/third-party certs; crane supervisor present
Hazard: Falls into excavation
Consequence: Major injury
Engineering/Procedural Control: Edge protection 1.1 m, toe boards; controlled access; lighting; crossings with trench plates rated for load
PPE: Helmets, boots
Collective Measure: Guardrails and covers
Inspection/Permit/Supervision: Daily HSE inspections; after-hours security
Hazard: Ingress of water and flooding
Consequence: Loss of ground, drowning risk, collapse
Engineering/Procedural Control: Dewatering with standby pumps and high-level alarms; sump management; weather watch; stop-work criteria if inflow exceeds capacity
PPE: Waterproof boots, gloves; lifejackets if working near open water bodies
Collective Measure: Emergency egress ladders; escape routes
Inspection/Permit/Supervision: Dewatering logs; weekly function test of standby pumps
Hazard: Hazardous atmosphere (contaminated ground, H2S in storm sewers)
Consequence: Poisoning, asphyxiation
Engineering/Procedural Control: Pre-work ground contamination review; atmospheric testing before entry if indicators present; forced ventilation if required; treat deep, narrow sections as potential confined spaces when criteria met
PPE: Gas monitor, respiratory protection if authorized
Collective Measure: Access control and rescue plan
Inspection/Permit/Supervision: Confined Space PTW when applicable [Verify per project HSE plan and local regulations]
Hazard: Spoil pile instability/rolling objects
Consequence: Struck-by, edge overload
Engineering/Procedural Control: Keep spoil ≥0.6–1.0 m from edge; bench spoil; use stop blocks for trucks
PPE: Helmets, boots
Collective Measure: Physical edge markers and berms
Inspection/Permit/Supervision: Foreman checks each shift
Hazard: Noise/vibration from pumps and plant
Consequence: Hearing loss, nuisance, structural impact
Engineering/Procedural Control: Acoustic shrouds; limit hours; vibration monitoring near sensitive structures; low-vibration methods
PPE: Hearing protection
Collective Measure: Barriers and enclosures
Inspection/Permit/Supervision: Noise and vibration logs; compliance with permits
Hazard: Slips/trips from hoses, cables, uneven ground
Consequence: Minor/major injury
Engineering/Procedural Control: Hose ramps, cable management; housekeeping
PPE: Boots with good grip
Collective Measure: Defined walkways
Inspection/Permit/Supervision: Daily housekeeping inspection
Hazard: Traffic-plant interface
Consequence: Collision, injury
Engineering/Procedural Control: One-way plant routes; marshals; plant-person interface plan; reversing alarms and cameras
PPE: High-vis, helmets, boots
Collective Measure: Barriers and segregated walkways
Inspection/Permit/Supervision: TM inspections and audits by competent person
Hazard: Manual handling of drag hoses, panels
Consequence: Strains/sprains
Engineering/Procedural Control: Mechanical aids, team lifts, job rotation
PPE: Gloves, back support if approved
Collective Measure: Use machinery for moves
Inspection/Permit/Supervision: Supervisor oversight and training records

General Note: All controls to be verified against the project HSE plan and local regulations.

Environmental Controls

Dewatering and Water Quality

Provide treatment via settlement tanks/bags and filtration as needed. Target turbidity per permit (e.g., ≤50 NTU) and pH 6.0–9.0 [Verify]. No visible oil sheen; install absorbent booms.
Discharge only to approved outfalls; install flow meters and log discharge volumes.
Monitor drawdown to minimize settlement of adjacent assets; adjust pump rates and staging. Implement Trigger Action Response Plan (e.g., Alert: 50% of trigger; Action: 100% trigger) [Verify].

Erosion and Sediment Control

Perimeter controls: silt fence, fiber rolls, catch basin protection.
Stabilize stockpiles (covering, distance ≥10 m from drains where possible) and place ≥0.6–1.0 m from trench edge.
Maintain stabilized access/egress to prevent tracking.

Noise, Dust, and Vibration

Fit acoustic enclosures on pumps; limit night work where restricted.
Water spray for dust suppression; wheel wash as needed.
Monitor vibration where structures are within influence zone; set limits per project/geotechnical guidance [Verify].

Spills and Waste

Secondary containment for fuel and pumps; spill kits at each pump.
Segregate wastes; dispose via licensed carriers. No discharge of bentonite/polymer unless permitted.

Ecology and Community

Protect trees and habitats; no storage within dripline; use root protection boards if crossing.
Maintain public information signage and complaint log; respond within 24 h.

Permits and Reporting

Maintain water quality logs, waste transfer notes, noise/vibration monitoring records.
Stop-work if permit exceedances occur; notify Engineer and regulators as required.

Quality Assurance & Quality Control

Controls and Tolerances

Trench alignment and invert: tolerance ±10 mm on invert; gradient ±0.1%; alignment ±20 mm [Verify per project specifications].
Trench width: OD + working clearance + shoring system thickness [Verify].
Over-excavation: ≤50 mm; if exceeded, backfill with approved material and re-compact.
Shoring: verticality ≤1/100; spreader levels within ±10 mm; clearances per TWD.
Access: ladders at ≤7.5 m spacing; extend ≥1.0 m above surface; secured.

Testing and Frequency

Soil classification: Visual/manual logging to ASTM D2488; confirm against D2487 where lab data available.
Compaction: Nuclear density ASTM D6938 (or sand cone). Frequency: 1 test per 50 m of trench per lift, minimum 1 per lift per work area [Verify]. Acceptance: Pipe zone ≥95% MDD (Std Proctor); above-zone ≥98% to subgrade [Verify].
Water quality: Turbidity and pH at discharge start, then daily; additional tests after rainfall or pump changes [Verify].
Monitoring: Daily shoring inspection checklist; weekly summary to TWC; settlement/deflection per monitoring plan.

Calibration and Documentation

Instruments (laser, level, density gauge) with valid calibration (≤6 months for survey; per manufacturer for gauges) [Verify].
Maintain ITP checklists, inspection records, NCRs, and corrective actions. Provide as-built survey of trench invert if required.

Nonconformance and Corrective Action

Stop-work and make safe; notify Engineer; record NCR; implement corrective action (e.g., install additional shoring, re-compact, water treatment adjustment). Re-inspect before resuming.

Attachments

Shoring Temporary Works Design package (drawings, calculations, design check certificate)
Manufacturer’s data sheets and assembly/installation manuals (slide-rail/trench box)
Lifting plan and certificates for lifting equipment and accessories
Dewatering design (layout, pump sizing, monitoring plan, discharge permit)
Traffic Management Plan and permits
Excavation and Utility Crossing Permits; Potholing records
Risk Assessment/Method Statement (RAMS), Job Safety Analysis (JSA)
Daily Inspection Checklists (HSE and TWC), Shoring Inspection Logs
Calibration certificates (survey instruments, density gauges)
Water quality monitoring logs; vibration/noise monitoring records
As-built survey (if required) and NCR/Corrective Action reports

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ITP preview

The first inspection activities from the linked ITP for Method Statement: Deep Trench Excavation and Shoring Installation for Stormwater Mainlines:

Activity	Inspection / Test	Acceptance Criteria	Responsibility	Record
Pre-start documentation	Review of permits, TWD approval, lift plans	Approvals in place; permits current; risk assessments briefed	PM/TWC/QA-QC	ITP checklist, approvals
Utility clearance and potholing	Verification of locations vs as-builts	All utilities located and protected; hold point release	Utility Coordinator/Engineer	Pothole logs, redlines
Dewatering installation and commissioning	Drawdown test, pump flow check, discharge sampling	Water level ≥0.5–1.0 m below invert [Verify]; turbidity/pH within permit	Dewatering Subcontractor/Engineer	Commissioning sheet, water logs

Showing 3 of 10 inspection activities. View full ITP →

Related Inspection and Test Plan

An Inspection and Test Plan (ITP) is available for Method Statement: Deep Trench Excavation and Shoring Installation for Stormwater Mainlines. The ITP defines the inspection activities, acceptance criteria, hold and witness points, responsible parties, and records required to verify the work described in this method statement.

View the Method Statement: Deep Trench Excavation and Shoring Installation for Stormwater Mainlines ITP →

Frequently asked questions

Use slide-rail systems for deeper or longer linear excavations requiring minimal surface disruption and staged installation. Trench boxes suit shorter, uniform trenches and can be advanced as excavation progresses. Always follow the Temporary Works Design and manufacturer guidance.

Typically maintain the water table 0.5–1.0 m below trench invert along the working length to keep the formation dry and stable [Verify per dewatering design and permits].

A competent person must inspect shoring daily and after any event that could affect stability (e.g., heavy rain, impact). The TWC must sign off prior to first use and at defined hold points.

Typical acceptance is ≥95% MDD (Std Proctor) in the pipe zone and ≥98% above to subgrade, with testing frequency about one test per 50 m per lift [Verify per project specifications].

Temporary works design and checks, permits, lift plans, dewatering design and discharge permits, inspection checklists, calibration certificates, monitoring logs, and test results.