diff --git a/src/io/gpr/GprSurveyAssembler.cpp b/src/io/gpr/GprSurveyAssembler.cpp
index 041fce5..e9e3c2e 100644
--- a/src/io/gpr/GprSurveyAssembler.cpp
+++ b/src/io/gpr/GprSurveyAssembler.cpp
@@ -36,35 +36,14 @@ std::string readFileText(const std::string& path) {
   return ss.str();
 }
 
-}  // namespace
-
-geopro::core::GprSurvey assembleGprSurvey(
-    const std::vector<std::string>& channelIprbPaths,
-    const std::string& ordPath) {
-  // 1. .ord -> 各通道横偏（文件序）。
-  const std::vector<double> channelY0 =
-      parseChannelXOffsets(readFileText(ordPath));
-  if (channelY0.size() != channelIprbPaths.size()) {
-    throw std::runtime_error(
-        "通道数不一致: .ord 有效通道数与 .iprb 路径数量不符");
-  }
-  const std::size_t nchan = channelIprbPaths.size();
-  if (nchan == 0) {
-    throw std::runtime_error("无通道可装配");
-  }
-
-  // 2. 各通道读 header + BScan。
-  std::vector<IprHeader> headers;
-  std::vector<BScan> scans;
-  headers.reserve(nchan);
-  scans.reserve(nchan);
-  for (const std::string& iprbPath : channelIprbPaths) {
-    const IprHeader h = parseIprHeader(readFileText(toHeaderPath(iprbPath)));
-    headers.push_back(h);
-    scans.push_back(readIprb(iprbPath, h));
-  }
-
-  // 3. 校验 samples 一致；ntraces 取各通道 traces 最小值（对齐）。
+// 由各通道 .ord 横偏、header、已读 BScan 段装配 GprSurvey。
+// scans 已是待装配的道段（全线或 slab）；ntraces 取各通道段道数最小值（对齐）；
+// x0 由调用方给出（全线=0，slab=t0*dx）。samples 校验、Y 升序置换、值转置同源。
+geopro::core::GprSurvey assembleFromScans(const std::vector<double>& channelY0,
+                                          const std::vector<IprHeader>& headers,
+                                          const std::vector<BScan>& scans,
+                                          double x0) {
+  const std::size_t nchan = scans.size();
   const int samples = scans.front().samples;
   std::int64_t minTraces = scans.front().traces;
   for (std::size_t c = 0; c < nchan; ++c) {
@@ -74,16 +53,15 @@ geopro::core::GprSurvey assembleGprSurvey(
     minTraces = std::min(minTraces, scans[c].traces);
   }
 
-  // 4. 由首通道 header 定标尺。
   geopro::core::GprSurvey survey;
   survey.samples = samples;
   survey.ntraces = static_cast<int>(minTraces);
-  survey.x0 = 0.0;
+  survey.x0 = x0;
   survey.dx = headers.front().distanceInterval;
   survey.z0 = 0.0;
   survey.dz = (samples > 1) ? depthOfSample(1, headers.front()) : 0.0;
 
-  // 5. 按 Y 升序求置换：order[c] = 升序第 c 位对应的原通道索引。
+  // 按 Y 升序求置换：order[c] = 升序第 c 位对应的原通道索引。
   std::vector<std::size_t> order(nchan);
   std::iota(order.begin(), order.end(), std::size_t{0});
   std::stable_sort(order.begin(), order.end(),
@@ -111,4 +89,69 @@ geopro::core::GprSurvey assembleGprSurvey(
   return survey;
 }
 
+}  // namespace
+
+geopro::core::GprSurvey assembleGprSurvey(
+    const std::vector<std::string>& channelIprbPaths,
+    const std::string& ordPath) {
+  // 1. .ord -> 各通道横偏（文件序）。
+  const std::vector<double> channelY0 =
+      parseChannelXOffsets(readFileText(ordPath));
+  if (channelY0.size() != channelIprbPaths.size()) {
+    throw std::runtime_error(
+        "通道数不一致: .ord 有效通道数与 .iprb 路径数量不符");
+  }
+  const std::size_t nchan = channelIprbPaths.size();
+  if (nchan == 0) {
+    throw std::runtime_error("无通道可装配");
+  }
+
+  // 2. 各通道读 header + 全线 BScan。
+  std::vector<IprHeader> headers;
+  std::vector<BScan> scans;
+  headers.reserve(nchan);
+  scans.reserve(nchan);
+  for (const std::string& iprbPath : channelIprbPaths) {
+    const IprHeader h = parseIprHeader(readFileText(toHeaderPath(iprbPath)));
+    headers.push_back(h);
+    scans.push_back(readIprb(iprbPath, h));
+  }
+
+  // 3. 全线 x0=0；其余校验/标尺/排序/置换由公共 helper 完成。
+  return assembleFromScans(channelY0, headers, scans, 0.0);
+}
+
+geopro::core::GprSurvey assembleGprSurveySlab(
+    const std::vector<std::string>& channelIprbPaths,
+    const std::string& ordPath,
+    std::int64_t t0, std::int64_t t1) {
+  // 1. .ord -> 各通道横偏（文件序）。
+  const std::vector<double> channelY0 =
+      parseChannelXOffsets(readFileText(ordPath));
+  if (channelY0.size() != channelIprbPaths.size()) {
+    throw std::runtime_error(
+        "通道数不一致: .ord 有效通道数与 .iprb 路径数量不符");
+  }
+  const std::size_t nchan = channelIprbPaths.size();
+  if (nchan == 0) {
+    throw std::runtime_error("无通道可装配");
+  }
+
+  // 2. 各通道读 header + 仅 [t0,t1) 道段（readIprbRange 内做越界校验）。
+  std::vector<IprHeader> headers;
+  std::vector<BScan> scans;
+  headers.reserve(nchan);
+  scans.reserve(nchan);
+  for (const std::string& iprbPath : channelIprbPaths) {
+    const IprHeader h = parseIprHeader(readFileText(toHeaderPath(iprbPath)));
+    headers.push_back(h);
+    scans.push_back(readIprbRange(iprbPath, h, t0, t1));
+  }
+
+  // 3. x0 = t0*dx，使该段世界 X 与全线对齐；其余同全线装配。
+  const double dx = headers.front().distanceInterval;
+  return assembleFromScans(channelY0, headers, scans,
+                           static_cast<double>(t0) * dx);
+}
+
 }  // namespace geopro::io::gpr
diff --git a/src/io/gpr/GprSurveyAssembler.hpp b/src/io/gpr/GprSurveyAssembler.hpp
index d0da002..400ca22 100644
--- a/src/io/gpr/GprSurveyAssembler.hpp
+++ b/src/io/gpr/GprSurveyAssembler.hpp
@@ -1,6 +1,7 @@
 #ifndef GEOPRO_IO_GPR_GPRSURVEYASSEMBLER_HPP
 #define GEOPRO_IO_GPR_GPRSURVEYASSEMBLER_HPP
 
+#include <cstdint>
 #include <string>
 #include <vector>
 
@@ -23,6 +24,18 @@ geopro::core::GprSurvey assembleGprSurvey(
     const std::vector<std::string>& channelIprbPaths,
     const std::string& ordPath);
 
+// 只装配道区间 [t0,t1) 的 GprSurvey，各通道用 readIprbRange 只读该段，
+// 内存只随 slab 大小（非全线），供流式建体（B4 拼接）使用。
+//
+// 与 assembleGprSurvey 的差异：
+//   - ntraces = (t1-t0)，仅装配 [t0,t1) 道；
+//   - x0 = t0*dx（使 slab 世界 X 与全线对齐，B4 拼接靠此），其余标尺/排序/置换同上；
+//   - t0/t1 越界(t1>总道数 或 t0>t1 或 t0<0)、通道数不符、samples 不一致 抛 std::runtime_error。
+geopro::core::GprSurvey assembleGprSurveySlab(
+    const std::vector<std::string>& channelIprbPaths,
+    const std::string& ordPath,
+    std::int64_t t0, std::int64_t t1);
+
 }  // namespace geopro::io::gpr
 
 #endif  // GEOPRO_IO_GPR_GPRSURVEYASSEMBLER_HPP
diff --git a/tests/io/gpr/test_gpr_survey_assembler.cpp b/tests/io/gpr/test_gpr_survey_assembler.cpp
index a997649..d903852 100644
--- a/tests/io/gpr/test_gpr_survey_assembler.cpp
+++ b/tests/io/gpr/test_gpr_survey_assembler.cpp
@@ -65,6 +65,77 @@ TEST(GprSurveyAssembler, ThrowsWhenChannelCountMismatch) {
   std::filesystem::remove_all(d);
 }
 
+TEST(GprSurveyAssembler, SlabMatchesFullForRange) {
+  auto d = (std::filesystem::temp_directory_path() / "gpr_asm_slab").string();
+  std::filesystem::create_directories(d);
+  // 两通道各 4 道 (lastTrace=3), samples=2。
+  const char* HDR4 =
+      "SAMPLES: 2\nLAST TRACE: 3\nCHANNELS: 2\nTIMEWINDOW: 4.0\n"
+      "SOIL VELOCITY: 100.000000\nDISTANCE INTERVAL: 0.05\n";
+  writeText(d + "/A.iprh", HDR4);
+  writeI16(d + "/A.iprb", {10, 11, 12, 13, 14, 15, 16, 17});  // 4 道
+  writeText(d + "/B.iprh", HDR4);
+  writeI16(d + "/B.iprb", {20, 21, 22, 23, 24, 25, 26, 27});  // 4 道
+  writeText(d + "/x.ord", "0 1.0 -1.5 1\n1 0.0 -1.5 1\n");  // A->1.0, B->0.0
+
+  auto full = assembleGprSurvey({d + "/A.iprb", d + "/B.iprb"}, d + "/x.ord");
+  auto slab = assembleGprSurveySlab({d + "/A.iprb", d + "/B.iprb"}, d + "/x.ord",
+                                    1, 3);  // 道 [1,3)
+  EXPECT_EQ(slab.ntraces, 2);
+  EXPECT_EQ(slab.samples, full.samples);
+  EXPECT_NEAR(slab.dx, full.dx, 1e-9);
+  EXPECT_NEAR(slab.dz, full.dz, 1e-9);
+  EXPECT_NEAR(slab.z0, full.z0, 1e-9);
+  EXPECT_NEAR(slab.x0, full.x0 + 1 * full.dx, 1e-9);  // x0 对齐到 t0
+  ASSERT_EQ(slab.channelY.size(), full.channelY.size());
+  for (std::size_t c = 0; c < slab.channelY.size(); ++c) {
+    EXPECT_NEAR(slab.channelY[c], full.channelY[c], 1e-9);
+  }
+  // 值对拍: slab(c,t,s) == full(c, t+1, s)
+  for (int c = 0; c < static_cast<int>(slab.channelY.size()); ++c)
+    for (int t = 0; t < slab.ntraces; ++t)
+      for (int s = 0; s < slab.samples; ++s)
+        EXPECT_NEAR(slab.at(c, t, s), full.at(c, t + 1, s), 1e-9);
+  std::filesystem::remove_all(d);
+}
+
+TEST(GprSurveyAssembler, SlabOutOfRangeThrows) {
+  auto d = (std::filesystem::temp_directory_path() / "gpr_asm_slab_oob").string();
+  std::filesystem::create_directories(d);
+  const char* HDR4 =
+      "SAMPLES: 2\nLAST TRACE: 3\nCHANNELS: 2\nTIMEWINDOW: 4.0\n"
+      "SOIL VELOCITY: 100.000000\nDISTANCE INTERVAL: 0.05\n";
+  writeText(d + "/A.iprh", HDR4);
+  writeI16(d + "/A.iprb", {10, 11, 12, 13, 14, 15, 16, 17});  // 4 道
+  writeText(d + "/B.iprh", HDR4);
+  writeI16(d + "/B.iprb", {20, 21, 22, 23, 24, 25, 26, 27});  // 4 道
+  writeText(d + "/x.ord", "0 1.0 -1.5 1\n1 0.0 -1.5 1\n");
+  const std::vector<std::string> paths = {d + "/A.iprb", d + "/B.iprb"};
+  // t1 超总道数 (总道数=4)。
+  EXPECT_THROW(assembleGprSurveySlab(paths, d + "/x.ord", 2, 5),
+               std::runtime_error);
+  // t0 > t1。
+  EXPECT_THROW(assembleGprSurveySlab(paths, d + "/x.ord", 3, 1),
+               std::runtime_error);
+  std::filesystem::remove_all(d);
+}
+
+TEST(GprSurveyAssembler, SlabThrowsWhenChannelCountMismatch) {
+  auto d =
+      (std::filesystem::temp_directory_path() / "gpr_asm_slab_cm").string();
+  std::filesystem::create_directories(d);
+  const char* HDR4 =
+      "SAMPLES: 2\nLAST TRACE: 3\nCHANNELS: 2\nTIMEWINDOW: 4.0\n"
+      "SOIL VELOCITY: 100.000000\nDISTANCE INTERVAL: 0.05\n";
+  writeText(d + "/A.iprh", HDR4);
+  writeI16(d + "/A.iprb", {10, 11, 12, 13, 14, 15, 16, 17});
+  writeText(d + "/x.ord", "0 1.0 -1.5 1\n1 0.0 -1.5 1\n");  // 2 有效通道
+  // 只传 1 个 iprb 路径 -> 抛错。
+  EXPECT_THROW(assembleGprSurveySlab({d + "/A.iprb"}, d + "/x.ord", 1, 3),
+               std::runtime_error);
+  std::filesystem::remove_all(d);
+}
+
 TEST(GprSurveyAssembler, AlignsTracesToMinimum) {
   auto d = (std::filesystem::temp_directory_path() / "gpr_asm_align").string();
   std::filesystem::create_directories(d);