{"id":4708,"date":"2025-11-04T09:41:53","date_gmt":"2025-11-04T09:41:53","guid":{"rendered":"https:\/\/eurohinca.com\/?p=4708"},"modified":"2025-11-04T09:43:02","modified_gmt":"2025-11-04T09:43:02","slug":"which-geotechnical-hazards-are-most-likely-to-be-encountered-by-type-of-terrain-and-how-to-mitigate-them-effectively","status":"publish","type":"post","link":"https:\/\/eurohinca.com\/en\/que-riesgos-geotecnicos-son-mas-probables-por-tipo-de-terreno-y-como-se-mitigan-eficazmente\/","title":{"rendered":"What geotechnical hazards are most likely by soil type and how are they effectively mitigated?"},"content":{"rendered":"
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At pipe jacking (microtunneling)<\/a><\/strong>, the risks depend on the type of soil<\/strong>, the water table (NF)<\/strong> and the front pressure<\/strong>. Mitigation combines shield selection (EPB\/hydro-shield\/mixed)<\/strong>, soil\/sludge conditioning<\/strong>, lubrication and injections<\/strong>, y monitoring<\/strong> of thrusts and pressures.<\/p>

Rapid risk mapping by terrain and effective response<\/h4>
Terrain \/ Condition<\/th>Probable risks<\/th>Operational (on-site) mitigation<\/th>Preliminary \/ design measures<\/th><\/tr><\/thead>
Loose sands (high NF)<\/strong><\/td>Loss of land, siphoning\/piping<\/strong>, settlements<\/td>Fine control of chamber pressure<\/strong>, suitable rheology (EPB\/hydro-shield), lubrication<\/strong> continues<\/td>NF pre-drainage\/depression, screens\/curtains, traverses with sufficient cover<\/td><\/tr>
Dense sands<\/strong><\/td>Torque overconsumption, deviations, wear and tear<\/td>Conditioning (foam\/polymers), stable feed rate, smooth corrections<\/td>Straight or Rmin<\/strong> wide; choice of suitable pikes and shields<\/td><\/tr>
Silt\/soft clays<\/strong><\/td>Instability of the front, deformations, ovalization<\/td>Stable pressure, constant feed rate, injected<\/strong> back<\/td>Local enhancement (jet\/grouting) if sensitive structures are present<\/td><\/tr>
Overconsolidated clays<\/strong><\/td>High friction, high thrusts<\/strong>, deviations, deviations<\/td>Lubrication<\/strong> (bentonite\/polymers), thrust control, recalibration pauses, etc.<\/td>Conservative thrust calculation; launch liner<\/td><\/tr>
Gravels\/boulders<\/strong><\/td>Blockages, roll-downs, detours<\/td>Head with reinforced picks\/cutters, high torque, injections<\/strong> stabilization<\/td>Input\/output buffers, localized pre-treatments<\/td><\/tr>
Mixed\/heterogeneous soils<\/strong><\/td>Sudden changes in pressure, loss of terrain<\/td>Mixed-mode (EPB\/Slurry), data-driven rheology transition<\/td>Previous reconnaissance (surveys, geophysics), windows<\/strong> inspection<\/td><\/tr>
Fractured rock<\/strong><\/td>Water inflow, over-excavation, settlements<\/td>Front sealing, pressure control, phased advance<\/td>Pre-bolting\/plastering, additional coverage<\/td><\/tr>
Karst\/cavities<\/strong><\/td>Voids, collapse, subsidence<\/td>Filling\/injections, guided by radar\/GPR<\/strong> during the work<\/td>Recognition and variant development<\/strong>; exclusion if the risk is critical<\/td><\/tr>
Anthropic landfills<\/strong><\/td>Hard objects, leaks, differential seating<\/td>Low speed, reconnaissance stops, shirts<\/strong> temporary<\/td>Tastings\/test wells, path screening<\/td><\/tr>
NF variable \/ tides<\/strong><\/td>Pressure changes, water inlets<\/td>Hydroshield, bypass<\/strong> emergency, valve control<\/td>Programming by hydrological window, sheet piles on coastline<\/td><\/tr><\/tbody><\/table><\/div><\/div>

How to reduce probability and impact (step by step)<\/h4>

  1. Do your research<\/strong>The following are some of the most important services: boreholes with recovery, piezometers, geophysics (GPR\/seismic) and affected services.<\/p><\/li>

  2. Design for the worst case<\/strong>minimum coverage, Rmin<\/strong> reasonable, calculation of thrust and choice of shield.<\/p><\/li>

  3. Prepare the ground<\/strong> where it touches: NF depression<\/strong>, injections\/jet grouting, screens.<\/p><\/li>

  4. Control parameters in real time<\/strong>Front pressure, flow rate\/rheology, thrust and torque, injection volume; land balance<\/strong>.<\/p><\/li>

  5. Define alarm thresholds and stop rules<\/strong>: e.g., \u0394warming, \u0394pressure, loss ratio \u2192 pause, stabilize, inject, resume<\/strong>.<\/p><\/li>

  6. Closes well<\/strong>: as-built<\/strong> geometric, tightness tests and QA\/QC report per section.<\/p><\/li><\/ol>

    Warning signs (act immediately)<\/h4>