diff --git a/B08_Quantity/B08_Quantity_Engine_Handoff_Trench.py b/B08_Quantity/B08_Quantity_Engine_Handoff_Trench.py
index 2460cfc1..cdc64087 100644
--- a/B08_Quantity/B08_Quantity_Engine_Handoff_Trench.py
+++ b/B08_Quantity/B08_Quantity_Engine_Handoff_Trench.py
@@ -111,7 +111,10 @@ def structure_earthwork_rows(
     unit_quantity_table: dict[str, Any], mapping: WorkItemMapping
 ) -> tuple[list[dict[str, Any]], list[str]]:
     """구조물이 낸 터파기·되메우기·잔토를 **공종 축**으로 올린다."""
-    trench: dict[tuple[str, str | None, str], float] = {}
+    # ⚠ 키는 **(심도, 토질)** 뿐이다 — 근거 문구까지 키에 넣으면 같은 「암절취 · 2~3m」이
+    #   측점 문구가 다르다는 이유로 **두 줄로 갈린다**(2026-09-08 실화면에서 그랬다).
+    trench: dict[tuple[str, str | None], float] = {}
+    bases: dict[tuple[str, str | None], list[str]] = {}
     backfill = 0.0
     spoil = 0.0
     for structure in unit_quantity_table.get("structures") or []:
@@ -128,8 +131,11 @@ def structure_earthwork_rows(
             if amount <= 0:
                 continue
             if name == "터파기":
-                key = (band, ground, ground_basis)
+                key = (band, ground)
                 trench[key] = trench.get(key, 0.0) + amount
+                reasons = bases.setdefault(key, [])
+                if ground_basis and ground_basis not in reasons:
+                    reasons.append(ground_basis)
             elif name == "되메우기":
                 backfill += amount
             elif name == "잔토처리":
@@ -143,11 +149,12 @@ def structure_earthwork_rows(
         if code is None:
             unmatched.append(TRENCH_GROUP)
         order = [band for _, band in DEPTH_BANDS] + [DEPTH_OVER]
-        for (band, ground, ground_basis), amount in sorted(
+        for (band, ground), amount in sorted(
             trench.items(), key=lambda item: (order.index(item[0][0]), str(item[0][1] or ""))
         ):
             if not amount:
                 continue
+            ground_basis = " · ".join(bases.get((band, ground)) or [])
             label = GROUND_TYPE_LABEL.get(str(ground), str(ground)) if ground else None
             reason = WATER_BLOCKED_REASON if ground else f"{GROUND_BLOCKED_REASON} — {ground_basis}"
             rows.append(