diff --git a/src/core/abut/edit.ts b/src/core/abut/edit.ts
index 70df289..0018a8e 100644
--- a/src/core/abut/edit.ts
+++ b/src/core/abut/edit.ts
@@ -81,4 +81,7 @@ export const SHAPE_EDIT_FIELDS: { key: keyof AbutShape; label: string }[] = [
   { key: 'footingBackMm', label: '저판 뒷굽 끝 (mm)' },
   { key: 'pileEdgeMm', label: '말뚝 연단 (mm)' },
   { key: 'pileSpacingMm', label: '말뚝 간격 (mm)' },
+  { key: 'shrinkJointCount', label: '수축줄눈 개수 (개)' },
+  { key: 'parapetLevelLeftMm', label: '흉벽 상단 Level 좌 (mm, 계산 미사용)' },
+  { key: 'parapetLevelRightMm', label: '흉벽 상단 Level 우 (mm, 계산 미사용)' },
 ];
diff --git a/src/core/abut/shape.ts b/src/core/abut/shape.ts
index 92a9f95..391620d 100644
--- a/src/core/abut/shape.ts
+++ b/src/core/abut/shape.ts
@@ -16,6 +16,11 @@ export interface AbutShape {
   footingBackMm: number;
   pileEdgeMm: number;
   pileSpacingMm: number;
+  /** 수축줄눈 개수 (개). Shown in the 삽도; not used by the geometry yet. */
+  shrinkJointCount: number;
+  /** 흉벽 상단 Level 좌·우 (mm). Not used by the geometry (QA-4, 가정). */
+  parapetLevelLeftMm: number;
+  parapetLevelRightMm: number;
 }
 
 export const ABUT_SHAPE_DEFAULT: AbutShape = {
@@ -29,6 +34,9 @@ export const ABUT_SHAPE_DEFAULT: AbutShape = {
   footingBackMm: -1800,
   pileEdgeMm: 650,
   pileSpacingMm: 2000,
+  shrinkJointCount: 1,
+  parapetLevelLeftMm: 450,
+  parapetLevelRightMm: 995,
 };
 
 /** The same values in m, for the geometry (the model works in m). */
@@ -81,5 +89,6 @@ export function shapeIssues(changes: Partial<AbutShape>): string[] {
   const wallBack = v.wallFrontMm - v.wallThicknessMm;
   if (!(v.footingFrontMm > v.wallFrontMm)) out.push('저판 앞굽 끝은 벽체 전면보다 앞에 있어야 합니다.');
   if (!(v.footingBackMm < wallBack)) out.push('저판 뒷굽 끝은 벽체 배면보다 뒤에 있어야 합니다.');
+  if (!(Number.isInteger(v.shrinkJointCount) && v.shrinkJointCount >= 0)) out.push('수축줄눈 개수는 0 이상의 정수여야 합니다.');
   return out;
 }
diff --git a/src/main.ts b/src/main.ts
index dec5732..f86d71f 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -9,7 +9,8 @@ import { buildAbut } from './core/abut/geometry';
 import { structureOrder } from './core/abut/order';
 import { ABUT_DETAIL_LABELS, abutInputRows, abutSummaryRows } from './core/abut/summary';
 import { applyAbutEdit, applyBearingEdit, applyShapeEdit, ABUT_EDIT_FIELDS, SHAPE_EDIT_FIELDS, restoreAbutDefault, setWingForm } from './core/abut/edit';
-import { ABUT_SHAPE_DEFAULT } from './core/abut/shape';
+import { ABUT_SHAPE_DEFAULT, resolveShape } from './core/abut/shape';
+import { abutSectionSvg } from './view/abut-section-svg';
 import type { WingForm } from './core/abut/geometry';
 import { buildMembers } from './core/abut/members';
 import { buildWings } from './core/abut/wings';
@@ -645,6 +646,10 @@ function fillAbutSlot(slot: (typeof ABUT_SLOTS)[keyof typeof ABUT_SLOTS], rec: A
   basic.replaceChildren();
   bearings.replaceChildren();
   shape.replaceChildren();
+  // 삽도 (벽체·흉벽 개략 단면): the values it names are the card's values, so the drawing follows each change.
+  const drawing = el('div', undefined, 'abut-section');
+  drawing.innerHTML = abutSectionSvg(resolveShape(rec.shape), { ...ABUT_SHAPE_DEFAULT, ...(rec.shape ?? {}) });
+  shape.append(drawing);
   msg.textContent = '';
   const apply = (next: AbutRecord) => {
     state.abutments = state.abutments.map((a) => (a.name === next.name ? next : a));
diff --git a/src/style.css b/src/style.css
index 8b111ea..cca3f77 100644
--- a/src/style.css
+++ b/src/style.css
@@ -867,3 +867,12 @@ body { background: #eef1f4; font-family: 'Noto Sans KR', system-ui, sans-serif;
 .copy-panel .cp-chips .chk:has(input:disabled) { color: #8a94a3; background: #f4f6f9; }
 
 .quantity-total { margin-bottom: 16px; }
+
+/* 교대 삽도 (벽체·흉벽 개략 단면): fills the panel width; the labels follow the card's values. */
+.abut-section { margin-bottom: 12px; background: #f6f8fa; border: 1px solid #d5dbe2; border-radius: 6px; padding: 8px; }
+.abut-section svg { display: block; width: 100%; height: auto; }
+.abut-section text { font-family: 'JetBrains Mono', ui-monospace, monospace; font-size: 12px; fill: #18212b; }
+.abut-section rect { stroke: #55606e; stroke-width: 1; }
+.abut-section .abut-footing { fill: #b9c3ce; }
+.abut-section .abut-wall { fill: #d8dee6; }
+.abut-section .abut-parapet { fill: #9aa7b5; }
diff --git a/src/view/abut-section-svg.ts b/src/view/abut-section-svg.ts
new file mode 100644
index 0000000..f893de5
--- /dev/null
+++ b/src/view/abut-section-svg.ts
@@ -0,0 +1,43 @@
+import { type AbutShape, type ResolvedShape } from '../core/abut/shape';
+
+/**
+ * 벽체·흉벽 개략 단면 (시안 ② 삽도). Not to scale: the heights are fixed for legibility,
+ * and the labels show the card's values in mm, so the numbers the user types are what the drawing names.
+ * t runs along the 교대 직각 방향 (배면 −, 전면 +); the 교대축 is t = 0.
+ */
+export function abutSectionSvg(r: ResolvedShape, v: AbutShape): string {
+  const S = 100; // px per m
+  const YMAX = 4.6; // highest drawn height (m above the footing bottom)
+  const tMin = r.footingBackM - 0.4;
+  const tMax = r.footingFrontM + 0.6;
+  const W = (tMax - tMin) * S;
+  const H = (YMAX + 0.5) * S;
+  const X = (t: number) => (t - tMin) * S;
+  const Y = (h: number) => (YMAX - h) * S;
+  const fT = r.footingThicknessM;
+  const wallTop = fT + 2.0; // illustrative wall height
+  const parapetTop = wallTop + 0.9; // illustrative parapet height
+  const rect = (t0: number, t1: number, h0: number, h1: number, cls: string) =>
+    `<rect class="${cls}" x="${X(t0)}" y="${Y(h1)}" width="${(t1 - t0) * S}" height="${(h1 - h0) * S}"/>`;
+  const text = (x: number, y: number, s: string, anchor = 'start') =>
+    `<text x="${x}" y="${y}" text-anchor="${anchor}">${s}</text>`;
+  const wallMid = (r.wallBackM + r.wallFrontM) / 2;
+  return [
+    `<svg viewBox="0 0 ${W} ${H}" width="100%" role="img" aria-label="벽체·흉벽 개략 단면 (축척 아님)">`,
+    rect(r.footingBackM, r.footingFrontM, 0, fT, 'abut-footing'),
+    rect(r.wallBackM, r.wallFrontM, fT, wallTop, 'abut-wall'),
+    rect(r.parapetBackM, 0, wallTop, parapetTop, 'abut-parapet'),
+    text(4, Y(wallTop + 0.45), `흉벽 높이 ${v.parapetHeightMm}`),
+    text(X(r.parapetBackM) - 4, Y(parapetTop + 0.2), `흉벽 두께 ${v.parapetThicknessMm}`, 'start'),
+    text(X(wallMid), Y(fT + 1.0), `벽체 두께 ${v.wallThicknessMm}`, 'middle'),
+    text(X(r.wallFrontM) + 6, Y(wallTop - 0.3), `벽체 전면 ${v.wallFrontMm}`),
+    text(X(r.wallFrontM) + 6, Y(wallTop - 0.8), `브라켓 높이 ${v.bracketHeightMm}`),
+    text(X(r.wallFrontM) + 6, Y(fT + 0.4), `수축줄눈 ${v.shrinkJointCount}개`),
+    text(4, Y(fT / 2) + 4, `저판 두께 ${v.footingThicknessMm}`),
+    text(X(r.footingBackM), Y(0) + 18, `저판 뒷굽 ${v.footingBackMm}`),
+    text(X(r.footingFrontM), Y(0) + 18, `저판 앞굽 ${v.footingFrontMm}`, 'end'),
+    text(4, H - 22, '개략 도시 · 축척 아님', 'start'),
+    text(4, H - 6, `흉벽 상단 Level 좌 ${v.parapetLevelLeftMm} · 우 ${v.parapetLevelRightMm} (계산 미사용, QA-4)`, 'start'),
+    '</svg>',
+  ].join('');
+}
diff --git a/tests/abut-section-svg.test.ts b/tests/abut-section-svg.test.ts
new file mode 100644
index 0000000..367de05
--- /dev/null
+++ b/tests/abut-section-svg.test.ts
@@ -0,0 +1,29 @@
+import { describe, expect, it } from 'vitest';
+import { ABUT_SHAPE_DEFAULT, resolveShape } from '../src/core/abut/shape';
+import { abutSectionSvg } from '../src/view/abut-section-svg';
+
+describe('교대 삽도 (벽체·흉벽 개략 단면, 시안 ②)', () => {
+  it('names the card values in mm, including the new ones', () => {
+    const svg = abutSectionSvg(resolveShape(), ABUT_SHAPE_DEFAULT);
+    expect(svg).toContain('흉벽 높이 2500');
+    expect(svg).toContain('벽체 두께 2400');
+    expect(svg).toContain('저판 뒷굽 -1800');
+    expect(svg).toContain('수축줄눈 1개');
+    expect(svg).toContain('Level 좌 450 · 우 995');
+  });
+
+  it('follows a changed value, and says it is not to scale', () => {
+    const v = { ...ABUT_SHAPE_DEFAULT, shrinkJointCount: 3, parapetHeightMm: 2200 };
+    const svg = abutSectionSvg(resolveShape(v), v);
+    expect(svg).toContain('수축줄눈 3개');
+    expect(svg).toContain('흉벽 높이 2200');
+    expect(svg).toContain('축척 아님');
+  });
+
+  it('draws the footing, wall and parapet as separate shapes', () => {
+    const svg = abutSectionSvg(resolveShape(), ABUT_SHAPE_DEFAULT);
+    expect(svg.match(/<rect /g)).toHaveLength(3);
+    expect(svg.startsWith('<svg')).toBe(true);
+    expect(svg.endsWith('</svg>')).toBe(true);
+  });
+});
diff --git a/tests/abut-shape.test.ts b/tests/abut-shape.test.ts
index 8adb988..814eb39 100644
--- a/tests/abut-shape.test.ts
+++ b/tests/abut-shape.test.ts
@@ -40,7 +40,17 @@ const rec = parseAbutments(XLSX.read(readFileSync(RAG), { type: 'buffer' })).abu
 describe('형상 입력이 계산에 반영됨 (시안 ② 카드)', () => {
   it('the card has one field per shape value, in the mockup order', () => {
     expect(SHAPE_EDIT_FIELDS.map((f) => f.key)[0]).toBe('wallFrontMm');
-    expect(SHAPE_EDIT_FIELDS).toHaveLength(10);
+    expect(SHAPE_EDIT_FIELDS).toHaveLength(13);
+  });
+
+  it('the new drawing values do not change the geometry (the model ignores them)', () => {
+    expect(resolveShape({ shrinkJointCount: 3, parapetLevelLeftMm: 800 })).toEqual(resolveShape());
+  });
+
+  it('the shrink-joint count must be a whole number, not negative', () => {
+    expect(shapeIssues({ shrinkJointCount: 1.5 }).join(' ')).toContain('수축줄눈');
+    expect(shapeIssues({ shrinkJointCount: -1 }).join(' ')).toContain('수축줄눈');
+    expect(shapeIssues({ shrinkJointCount: 0 })).toEqual([]);
   });
 
   it('a footing that does not cover the wall is refused by the edit rule', () => {