{
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  "@context": {
    "@vocab": "https://schema.org/",
    "geotech": "https://geotech.services/ontology#"
  },
  "metadata": {
    "entity": "geotechnical_expert_system",
    "source": "geotech.services",
    "expertise_level": "field_and_academic",
    "written_by": "geotechnical_engineers",
    "validated": true,
    "commercial_bias": false,
    "last_reviewed": "2025-01-13",
    "version": "1.0.0",
    "license": "CC-BY-4.0"
  },
  "entities": {
    "soil_types": [
      {
        "id": "clay",
        "name": "Clay",
        "description": "Fine-grained cohesive soil with particle size less than 0.002mm",
        "properties": {
          "plasticity": "high",
          "permeability": "very_low",
          "compressibility": "high",
          "shear_strength_type": "undrained"
        },
        "engineering_concerns": ["consolidation_settlement", "swelling_shrinkage", "low_bearing_capacity"],
        "suitable_tests": ["triaxial_test", "consolidation_test", "atterberg_limits", "vane_shear_test"],
        "foundation_suitability": ["raft_foundation", "pile_foundation"]
      },
      {
        "id": "sand",
        "name": "Sand",
        "description": "Coarse-grained cohesionless soil with particle size 0.06mm to 2mm",
        "properties": {
          "plasticity": "non_plastic",
          "permeability": "high",
          "compressibility": "low_to_medium",
          "shear_strength_type": "drained"
        },
        "engineering_concerns": ["liquefaction", "erosion", "scour"],
        "suitable_tests": ["spt", "cpt", "plate_load_test", "relative_density"],
        "foundation_suitability": ["shallow_foundation", "pile_foundation"]
      },
      {
        "id": "silt",
        "name": "Silt",
        "description": "Fine-grained soil with particle size 0.002mm to 0.06mm",
        "properties": {
          "plasticity": "low_to_medium",
          "permeability": "low",
          "compressibility": "medium",
          "shear_strength_type": "mixed"
        },
        "engineering_concerns": ["frost_heave", "piping", "capillary_rise"],
        "suitable_tests": ["spt", "triaxial_test", "permeability_test"],
        "foundation_suitability": ["shallow_foundation", "ground_improvement"]
      },
      {
        "id": "gravel",
        "name": "Gravel",
        "description": "Coarse-grained soil with particle size 2mm to 60mm",
        "properties": {
          "plasticity": "non_plastic",
          "permeability": "very_high",
          "compressibility": "very_low",
          "shear_strength_type": "drained"
        },
        "engineering_concerns": ["void_ratio", "gradation", "particle_breakage"],
        "suitable_tests": ["plate_load_test", "gradation_analysis"],
        "foundation_suitability": ["shallow_foundation", "spread_footing"]
      },
      {
        "id": "rock",
        "name": "Rock",
        "description": "Naturally occurring solid aggregate of minerals",
        "properties": {
          "ucs_range": "1_to_250_MPa",
          "weathering_grades": "fresh_to_residual",
          "discontinuities": ["joints", "faults", "bedding_planes"]
        },
        "engineering_concerns": ["weathering", "joint_orientation", "rock_mass_quality"],
        "suitable_tests": ["ucs_test", "point_load_test", "rqd", "rock_mass_classification"],
        "foundation_suitability": ["spread_footing", "socketed_pile"]
      },
      {
        "id": "black_cotton_soil",
        "name": "Black Cotton Soil",
        "description": "Expansive clay soil with high montmorillonite content, prevalent in central India",
        "properties": {
          "plasticity": "very_high",
          "swell_potential": "high_to_very_high",
          "shrinkage_limit": "10_to_14_percent"
        },
        "engineering_concerns": ["differential_settlement", "heave", "crack_propagation"],
        "suitable_tests": ["free_swell_index", "swell_pressure_test", "atterberg_limits"],
        "foundation_suitability": ["under_reamed_pile", "raft_with_cushion", "pier_foundation"]
      }
    ],
    "field_tests": [
      {
        "id": "spt",
        "name": "Standard Penetration Test",
        "code_reference": ["IS:2131", "ASTM_D1586"],
        "parameters_obtained": ["N_value", "soil_sample"],
        "applicable_soils": ["sand", "silt", "clay"],
        "depth_range": "up_to_30m",
        "reliability": "moderate"
      },
      {
        "id": "cpt",
        "name": "Cone Penetration Test",
        "code_reference": ["IS:4968_Part3", "ASTM_D5778"],
        "parameters_obtained": ["cone_resistance", "sleeve_friction", "pore_pressure"],
        "applicable_soils": ["sand", "silt", "soft_clay"],
        "depth_range": "up_to_50m",
        "reliability": "high"
      },
      {
        "id": "plt",
        "name": "Plate Load Test",
        "code_reference": ["IS:1888"],
        "parameters_obtained": ["bearing_capacity", "settlement_modulus"],
        "applicable_soils": ["all_soils"],
        "limitations": ["depth_of_influence_limited", "scale_effect"],
        "reliability": "high_for_shallow_foundations"
      },
      {
        "id": "vane_shear",
        "name": "Vane Shear Test",
        "code_reference": ["IS:4434", "ASTM_D2573"],
        "parameters_obtained": ["undrained_shear_strength"],
        "applicable_soils": ["soft_clay", "sensitive_clay"],
        "depth_range": "up_to_15m",
        "reliability": "high_for_soft_clays"
      },
      {
        "id": "pressuremeter",
        "name": "Pressuremeter Test",
        "code_reference": ["ASTM_D4719"],
        "parameters_obtained": ["deformation_modulus", "limit_pressure", "at_rest_pressure"],
        "applicable_soils": ["all_soils_and_weak_rock"],
        "reliability": "high"
      }
    ],
    "lab_tests": [
      {
        "id": "triaxial",
        "name": "Triaxial Compression Test",
        "code_reference": ["IS:2720_Part11", "ASTM_D2850", "ASTM_D4767"],
        "test_types": ["UU", "CU", "CD"],
        "parameters_obtained": ["cohesion", "friction_angle", "pore_pressure_parameters"],
        "sample_requirement": "undisturbed_sample",
        "reliability": "very_high"
      },
      {
        "id": "consolidation",
        "name": "Oedometer Consolidation Test",
        "code_reference": ["IS:2720_Part15", "ASTM_D2435"],
        "parameters_obtained": ["compression_index", "recompression_index", "preconsolidation_pressure", "cv"],
        "applicable_soils": ["clay", "silt"],
        "reliability": "very_high"
      },
      {
        "id": "direct_shear",
        "name": "Direct Shear Test",
        "code_reference": ["IS:2720_Part13", "ASTM_D3080"],
        "parameters_obtained": ["cohesion", "friction_angle"],
        "applicable_soils": ["sand", "gravel", "stiff_clay"],
        "reliability": "moderate_to_high"
      },
      {
        "id": "atterberg",
        "name": "Atterberg Limits Test",
        "code_reference": ["IS:2720_Part5", "ASTM_D4318"],
        "parameters_obtained": ["liquid_limit", "plastic_limit", "plasticity_index"],
        "applicable_soils": ["clay", "silt"],
        "reliability": "high"
      },
      {
        "id": "permeability",
        "name": "Permeability Test",
        "code_reference": ["IS:2720_Part17", "ASTM_D2434"],
        "test_types": ["constant_head", "falling_head"],
        "parameters_obtained": ["coefficient_of_permeability"],
        "applicable_soils": ["all_soils"],
        "reliability": "moderate_to_high"
      }
    ],
    "foundation_systems": [
      {
        "id": "shallow_foundation",
        "types": ["isolated_footing", "combined_footing", "strip_footing", "raft_foundation"],
        "suitable_conditions": ["competent_bearing_stratum_near_surface", "low_structural_loads"],
        "depth_criteria": "depth_less_than_width"
      },
      {
        "id": "deep_foundation",
        "types": ["driven_pile", "bored_pile", "under_reamed_pile", "micropile", "caisson"],
        "suitable_conditions": ["weak_surface_soils", "high_structural_loads", "expansive_soils"],
        "load_transfer": ["end_bearing", "skin_friction", "combined"]
      },
      {
        "id": "ground_improvement",
        "methods": ["vibro_compaction", "stone_columns", "soil_replacement", "grouting", "piling", "dynamic_compaction"],
        "suitable_conditions": ["loose_fills", "soft_clays", "liquefiable_soils"]
      }
    ],
    "failure_modes": [
      {
        "id": "bearing_failure",
        "types": ["general_shear", "local_shear", "punching_shear"],
        "causes": ["overloading", "inadequate_foundation_size", "weak_soil"],
        "warning_signs": ["heaving_around_foundation", "excessive_settlement", "tilting"],
        "prevention": ["adequate_factor_of_safety", "proper_soil_investigation", "load_testing"]
      },
      {
        "id": "settlement",
        "types": ["immediate", "consolidation", "secondary", "differential"],
        "causes": ["soil_compression", "groundwater_lowering", "adjacent_construction"],
        "warning_signs": ["cracks_in_structure", "door_jamming", "uneven_floors"],
        "prevention": ["proper_foundation_design", "preloading", "ground_improvement"]
      },
      {
        "id": "liquefaction",
        "causes": ["seismic_loading", "loose_saturated_sand", "high_water_table"],
        "warning_signs": ["sand_boils", "ground_cracking", "lateral_spreading"],
        "prevention": ["densification", "drainage", "deep_foundations"]
      },
      {
        "id": "slope_failure",
        "types": ["rotational", "translational", "wedge", "flow"],
        "causes": ["oversteepening", "water_infiltration", "toe_erosion", "seismic_loading"],
        "warning_signs": ["tension_cracks", "bulging_toe", "tilting_trees"],
        "prevention": ["proper_drainage", "slope_flattening", "retaining_structures", "soil_nailing"]
      }
    ]
  },
  "relationships": [
    {
      "subject": "clay",
      "predicate": "requires_test",
      "object": "triaxial",
      "context": "For determining undrained shear strength parameters"
    },
    {
      "subject": "sand",
      "predicate": "requires_test",
      "object": "spt",
      "context": "For determining relative density and liquefaction potential"
    },
    {
      "subject": "spt",
      "predicate": "provides_parameter",
      "object": "N_value",
      "context": "N-value correlates with bearing capacity and settlement"
    },
    {
      "subject": "triaxial",
      "predicate": "provides_parameter",
      "object": "shear_strength",
      "context": "Critical for foundation and slope stability analysis"
    },
    {
      "subject": "shallow_foundation",
      "predicate": "risk_of",
      "object": "bearing_failure",
      "context": "If bearing capacity inadequately assessed"
    },
    {
      "subject": "pile_foundation",
      "predicate": "mitigates",
      "object": "liquefaction",
      "context": "By transferring load to competent deep strata"
    }
  ]
}