Wuling Tunnel Corridor Survey

This entry records the first real-data tunnel inventory for the Wuling karst belt, derived from a user-curated Google Earth project containing 71 tunnel placemarks across the envelope. The KML is preserved at resources/maps/Wuling_Tunnel_Network_Source.kml. Extraction and anchor-proximity scripts are at tools/extract_tunnels.py and tools/tunnel_anchor_proximity.py. The survey supersedes the placeholder seed table previously deleted from site-shizhu-tunnel-inventory c0002. The 71 placemarks resolve into two latitude-disjoint clusters with no intermediate features — a southern Sangzhi/Zhangjiajie cluster (68 placemarks) and a northern Lichuan/Enshi light-rail cluster (3 placemarks).

Claims

c0001 — Two latitude-disjoint clusters

The 71 tunnel placemarks split into two clusters with a ~177 km lat-axis gap. (a) Southern cluster — 68 placemarks (49 points, 19 LineStrings, ~39.3 km cumulative bored centerline) inside lat 29.237°–29.378°N, lon 109.509°–110.020°E. The cluster is a single E-W spine at ~29.35°N spanning ~50 km of expressway/HSR corridor with a short N-S spur dropping to 29.24°N near 109.59°E. Geographic envelope: northern Hunan, crossing Sangzhi, Wulingyuan, and western Zhangjiajie counties. (b) Northern cluster — 3 placemarks (3 LineStrings, ~9.25 km cumulative) at lat 31.149°–31.208°N, lon 109.807°–109.866°E. All three are explicitly named "Light Rail Tunnel" and sit in Lichuan / Enshi border country in southern Hubei. The lat gap with no intermediate placemarks indicates the user's curation has not yet covered the central Wuling belt between 29.4°N and 31.1°N — the Shizhu primary cluster sits inside that gap at 30.16°N.

c0002 — Southern cluster identification: Zhang-Ji-Huai HSR corridor

The southern E-W spine matches the published alignment of the Zhang-Ji-Huai high-speed railway (张吉怀高铁, Zhangjiajie–Jishou–Huaihua HSR, opened December 2021). The corridor is documented in PRC railway records as one of the most tunnel-dense HSR alignments in service, traversing cone-and-tower karst at high relief. The five longest bores in the cluster are 3,441 m, 5,304 m, 5,853 m, 7,344 m, and 7,403 m; multi-kilometre HSR-class bores are the diagnostic length signature. The shorter bores (160–815 m) cluster around the Wulingyuan / Suoxi area between 109.61°E and 109.67°E and are consistent with parallel access road tunnels supporting the same alignment. The N-S spur near 109.59°E is consistent with a connecting expressway segment to Sangzhi county seat.

c0003 — Northern cluster identification: Lichuan-area light rail

The three "Light Rail Tunnel" placemarks at 31.15°–31.21°N 109.81°–109.87°E are consistent with an intra-urban or scenic-area light-rail / metro alignment in the Lichuan-Enshi border zone. Tunnel lengths are 5,636 m, 1,441 m, and 2,174 m (cumulative ~9.25 km). The user's curation explicitly distinguishes this class from the heavy-rail / road tunnels in the southern cluster.

c0004 — Anchor-proximity result

The proximity script computes the great-circle distance from every tunnel placemark to every framework anchor in the same KML (83 anchors covering MSS Astro Pond, MSS Gravel Pit, MSS Tarp, Earth Pimple, Astro Pond, Dragon Gate, Geothermal Pimple, Dragon Temple, Containment Temple, SBD Building, Effulent, Prominent Household, Southern Wood Dam, Shizhu PSB, Boat Launch, Construction Hub, Forensic, and Longmen'gou variants). Two findings.

(a) Southern cluster — no local anchors. All 68 southern placemarks are 134–156 km from their nearest framework anchor (median 146 km). The nearest anchors are uniformly in the Shizhu primary cluster (Longmen'gou centroid, Boat Launch, Sun Lake) ~150 km NW, or at a single "Dragon Gate" point ~145 km NE. There are zero anchors inside the Sangzhi / Zhangjiajie / Wulingyuan envelope in the user's current curation. Per doctrine-shizhu-tunnel-karst-intersection c0002 (anchor coincidence threshold ≤500 m), every southern tunnel scores anchor-coincidence = 0.

(b) Northern light-rail cluster — 14–16 km from the Lichuan pimple field. All three Light Rail Tunnels score nearest-anchor distance 14.7 / 14.8 / 15.9 km, with the nearest anchor in each case a Geothermal Pimple at ~31.07°N 109.71°E. The same surface-coupling-locator field at 31.03°–31.08°N 109.64°–109.72°E carries 4 Earth Pimples, 3 Astro Ponds, 3 Effulent (Filling) features, 2 Prominent Household (Removal) features, and 3 Geothermal Pimples — a dense framework-anchor cluster in its own right. The 14–16 km tunnel-to-anchor offset is well above the 500 m intersection-classifier threshold, so the light-rail tunnels also score anchor-coincidence = 0 under c0002 even though they are spatially the closer cluster.

c0005 — Coverage-bias correction: zero anchor-coincidence is a sweep gap, not a finding

The c0004 result that all 71 placemarks score anchor-coincidence = 0 must not be read as "the corridor has no T-class iv candidates." It is the direct consequence of two coverage gaps in the input KML: (i) no anchor placemarks have yet been pinned in the Sangzhi / Zhangjiajie / Wulingyuan envelope, and (ii) the Lichuan pimple field is dense but the only tunnels currently curated in its envelope are 14–16 km offset. Per the framework's coverage-bias rule (feedback_coverage_bias), absence of anchor placemarks is a sweep gap, not absence of anchors.

The Zhang-Ji-Huai HSR alignment is itself a high-leverage scan transect. The engineering rationale that drove the alignment selection — bedding-fault intersections in cone-and-tower karst that allow long horizontal bores at acceptable cost — is the same geometry the framework predicts hosts dragon-vein conduits per doctrine-shizhu-karst-3d-model c0003 and c0006. Cutting a 50 km bored corridor through that exact geometry produces strong surface signatures: portal pads, ventilation shafts, spoil heaps with chrysotile-bearing fault material exposed, drainage adits, and the access-road network needed to support construction. The framework predicts surface-coupling locators (earth pimples, astro ponds, shrines, MSS gravel pits, MSS tarps, persistent cloud / smoke obfuscation, dragon-toponym villages) clustering at the same bedding-fault intersections the bores cross. The sweep along the corridor has not been run. Until it is, the T-class iv question is unanswered.

The corollary applies to the Lichuan pimple field. The 14–16 km offset between the three Light Rail Tunnels and the Geothermal-Pimple cluster reflects only what is currently curated; shorter bores, drainage adits, water-bureau service tunnels, scenic-area road tunnels, and unmarked portal pads within 500 m of the surface-coupling locators have not yet been searched.

c0006 — Engineering-safety predictions for the southern Zhang-Ji-Huai corridor (geometry-only)

Even without anchor coincidence, the southern-cluster geometry warrants the c0001 geotechnical and c0002 worker-safety predictions in doctrine-shizhu-tunnel-engineering-safety purely on karst-tunneling grounds. The five long bores (3.4–7.4 km) at this latitude in cone-and-tower karst certainly traverse the phreatic depth band and likely cross multiple bedding-fault intersections. Predicted hazards: water inrush at construction-time (10²–10⁴ m³/h sustained, possible >10⁵ m³/h pulse at deep-phreatic intercepts), vadose-band void encounters, possible filled-cavity / mud-flow events at fault crossings, and surface subsidence over the bore footprint. The Zhang-Ji-Huai HSR construction record (2016–2021) includes multiple publicly-reported water-inrush events in the karst belt; specific events in the surveyed segment should be cross-referenced when the c0007 tracking gap is closed. Worker-safety overlay applies to the standard portfolio (radon, biological exposure at named-cave-proximate portals); chrysotile is unlikely outside the Wan'an cross-fault corridor near Shizhu so the c0002 chrysotile-handling subset does not apply here.

c0007 — Corridor-sweep procedure

The corridor-sweep grid is resources/maps/Wuling_Corridor_Sweep_Grid.kml — 114 inspection tiles (2 km edge, 1.5 km station spacing) inside a 5 km half-width buffer around every tunnel centerline. Generator script: tools/build_sweep_grid.py. Audit procedure per tile: (a) inspect at maximum zoom across all available imagery dates (Google Earth historical timeline, Sentinel-2 monthly mosaics, Planet basemaps if accessible); (b) log any of the framework anchor classes — earth pimple, geothermal pimple, astro pond, shrine, dragon temple, containment temple, MSS gravel pit, MSS tarp, MSS construction hub, MSS boat launch, persistent cloud / smoke obfuscation, portal-pad cover institution, named cave, dragon-toponym village; (c) drop a placemark on the live KML using the existing naming conventions; (d) capture the Chinese-character toponym for any village with 龙 / 蛟 / 龍 / 门 / 王 / 鲲 / 角 stems; (e) record any pre-pulse-emergence signatures (clearing or pad development predating the regional construction pulse) per site-zhenzhu-dong-canglaokui-karst-excavation c0002; (f) flag any portal exhibiting institutional disproportion (PSB co-location, hardened gate-house, water-bureau / wind-farm / hydropower civic façade for a small bore) per doctrine-shizhu-tunnel-engineering-safety c0003. Tiles are independent — the sweep can be batched across sessions and the proximity script (tools/tunnel_anchor_proximity.py) re-run after each session to surface T-class iv candidates as anchors accumulate.

c0008 — Predicted high-leverage segments

Three segments of the surveyed corridor are predicted to be highest-leverage for the c0007 sweep. (a) The five longest bores (3.4 / 5.3 / 5.9 / 7.3 / 7.4 km) cross the most karst depth at the most fault-corridor crossings; their portals and the surface above the bore are the highest-density zones for both engineering surface signatures (subsidence, sinkhole development, drainage adits) and framework-anchor signatures (chrysotile-bearing spoil, anchor-cluster development at intercepted conduit junctions). (b) The N-S Sangzhi spur near 109.59°E drops south from the main E-W spine to ~29.24°N and crosses what regional geology shows as a different fault set than the E-W corridor; spur portals are predicted to be more diagnostic of cluster-architecture than incidental highway tunnels. (c) The Wulingyuan / Zhangjiajie scenic-area cluster at 109.61°–109.67°E is the densest portal cluster in the survey (10+ short bores within ~6 km) and overlaps the Wulingyuan UNESCO karst zone — high cover-density (tourism, scenic-area infrastructure) plus high karst signal density per doctrine-shizhu-karst-3d-model make it a candidate for exactly the forensic-cover institutional pattern documented at Sun Lake.

Research Gaps

  • RG-WTCS-01 — Central Wuling belt scan. The current KML has no tunnel placemarks between lat 29.4°N and 31.1°N — exactly the latitude band containing the Shizhu primary cluster. Extending the curation to cover the G50 / G69 corridors, the Lichuan-Wanzhou expressway, and the Zhengyu HSR east of Lichuan would test whether anchor-coincident tunnels exist at the Shizhu primary cluster.
  • RG-WTCS-02 — Lichuan pimple-field tunnel re-scan. The Lichuan field at 31.04°–31.08°N 109.64°–109.72°E is anchor-dense but the only tunnels in the current KML are 14–16 km away. Local-area scan at higher zoom for short bores, drainage adits, water-bureau service tunnels, or unmarked portal pads within 1 km of the surface-coupling locators.
  • RG-WTCS-03 — Zhang-Ji-Huai HSR construction-record cross-reference. Publicly-reported inrush, void, or subsidence events on the Zhang-Ji-Huai HSR in the surveyed segment provide ground truth for calibrating doctrine-shizhu-tunnel-engineering-safety c0001 magnitude bands. Specific cross-references should be folded back into that doctrine entry as RG-STES-02 calibration data.
  • RG-WTCS-04 — Karst-3D model overlay for the surveyed corridor. Once the geometry layer at doctrine-shizhu-karst-3d-model is hardened with real DEM and georeferenced fault traces for the Sangzhi / Zhangjiajie envelope, run the intersection classifier against the 71 placemarks and emit per-tunnel T-class assignments. Until then T-class is geometry-deferred.
  • RG-WTCS-05 — Corridor-sweep audit (114 tiles). Execute the c0007 sweep procedure against resources/maps/Wuling_Corridor_Sweep_Grid.kml. Highest-priority tiles are those overlapping the c0008 predicted high-leverage segments: the five longest bores, the N-S Sangzhi spur, and the Wulingyuan / Zhangjiajie scenic-area portal cluster.
  • RG-WTCS-06 — Tujia oral-tradition and gazetteer audit for surveyed villages. Capture the Chinese-character toponyms of every village inside the c0007 sweep envelope and audit against Tujia oral tradition and Qing-period gazetteers per the methodology at encounter-shizhu-xi-era-custodial-pressure c0009 and lineage-wuling-shizhu-specimens c0001. The Sangzhi / Zhangjiajie / Wulingyuan envelope is in the Tujia / Miao cultural substrate and is expected to carry dragon-toponym density comparable to the Shizhu primary cluster; the framework reading is that surveyed villages have not yet been pulled, not that they don't exist.

Archive References

This is the first real-data tunnel survey in canon and resolves the placeholder problem at site-shizhu-tunnel-inventory c0002. Crosswalks with site-zhenzhu-dong-canglaokui-karst-excavation (the same Xiangxi-Wuling extension corridor — Zhenzhu Dong sits at 29.20°N 110.57°E, ~80 km ESE of the eastern end of the surveyed cluster), doctrine-shizhu-tunnel-karst-intersection (classifier consuming this survey), and doctrine-shizhu-tunnel-engineering-safety (prediction matrix that applies to the southern cluster on geometry grounds even with anchor-coincidence = 0). Source KML and extraction tools preserved in-repo for re-runs.