HDD Planner

Preliminary HDD assessment of bore profile, pull force and bending radius based on DVGW GW 321 and a simplified force model.

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Overall Assessment

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Force Check —

Bending Radii —

SDR Suitability —

Material

Outside Diameter (dₑ)

SDR

Wall Thickness (s)

Entry Angle (α₁)

Exit Angle (α₂)

Cover Depth (H)

Total Crossing Length (L)

Soil Type

Soil Friction (μ_B)

Mud Friction (μ_S)

Mud Density (ρ)

kg/m³

Pipe on Rollers (L_R)

Safety Factor (S)

Pull Duration

Temperature

°C

Additional Load Allowancei

Bore Profile Section

Required Pull Force

Allowable Pull Force

Utilization Rate

Required Pull Force = Model Force T₄ - kN + Additional Load - kN

Reduced preliminary model: pull force and minimum bending radius per DVGW GW 321 plus simplified circular-arc geometry and capstan friction. Hydrokinetic, reaming, cutting, breakaway and stationary forces and collapse are not verified separately.

Force Progression

Entry Radius (R_in)

Exit Radius (R_ex)

Minimum Bending Radius

Bore Geometry & Segment Forces

Segment	kN
T₁	-
T₂	-
T₃	-
T₄ = F_erf	-

Horizontal Section (L₃)
- m

Pipe Weight
- kg/m

Net Buoyancy
- kg/m

Bending Stress
- N/mm²

Notice: This quick check is for orientation purposes only. The results do not replace a project-specific design. Dimensioning and approval are the responsibility of the responsible engineering office. All information without guarantee. Full Disclaimer

What is the HDD Planner?

The HDD Planner combines the three core HDD calculations in a single dashboard:

Bore Profile & Pull Force (GW 321 + Euler-Eytelwein): Is the pipe strong enough?
Bending Radius Check (DVGW GW 321, Table A.3): Are the temperature-dependent minimum radii met?
SDR Suitability: Is the wall thickness suitable for HDD?

The dashboard provides a preliminary assessment. A green result means that the simplified model indicates no issue; it is not a technical approval of the bore.

Workflow

Select pipe -> Define bore profile -> Soil & installation -> ✓ Result
    (1)             (2)                    (3)          Dashboard

Preliminary Assessment Criteria

Check	Green	Yellow	Red
Pull force	Utilization ≤ 70%	70-100%	> 100%
Bending radius	R/R_min ≥ 1.1	1.0-1.1	< 1.0
SDR	SDR ≤ 17	SDR > 17	-

Linked Detail Tools

The HDD Planner links directly to the individual calculators with pre-filled values:

Bore Profile Calculator - Detailed segment analysis with extended SVG visualization
Pull Force Calculator - Standard and Pro mode including bending influence
Bending Radius Calculator - Comparison of open trench installation vs. HDD

Calculation Basis

Standard	Scope
Circular-arc geometry / Euler-Eytelwein	Simplified 4-point profile and segment-wise capstan force balance
DVGW GW 321, Annex A	Pull-force and duration values plus temperature-dependent minimum bending radius; selectable safety factor $S$ is an additional internal planning reserve

All data provided without warranty. Full disclaimer

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