SPN soil boring rig working inside a petrochemical industrial estate in Rayong, with plant tanks and pipes in the background
Soil boring inside a petrochemical industrial estate, Rayong — work inside estates requires safety training, a work permit and plant-specified equipment before drilling can start

What services does SPN provide in Chon Buri, Rayong and the EEC?

SPN provides full-range geotechnical services in the Eastern region. Work we regularly carry out in this area includes:

  • Soil investigation (Soil Boring + SPT) — new factories and extensions, warehouses, liquid storage tanks, ports and infrastructure, with lab testing and engineer-certified reports
  • Field soil testing — Plate Bearing Test for factory floors and container yards · Field Density and DCP for controlling fill and road works in estates
  • Pile testing — Dynamic Load Test (PDA) per ASTM D4945 and DPT 1252-51 · Seismic Integrity Test per DPT 1551-51 · Static Load Test for factory piles and heavy machinery
  • Non-destructive structural testing (NDT) — chemical anchor Pull-Out Test, Core Test, Rebound Hammer and GPR for factories adding extensions or installing new machinery
  • Instrumentation installation — Settlement Plates and Piezometers for large-scale factory site filling and leveling

How do Chon Buri–Rayong soils differ from Bangkok?

Soil conditions in the Eastern region are far more variable than in Bangkok. While Bangkok and its vicinity have a fairly uniform thick layer of soft clay (Soft Bangkok Clay), the Chon Buri–Rayong area can change within a few kilometers. Typical conditions from SPN's actual projects are:

  • Coastal plains (the Chon Buri–Rayong coastline, including petrochemical estates) — usually coastal sand and marine sediments, with a high and possibly saline groundwater table. Watch for borehole collapse and plan fill works to suit the groundwater.
  • Inland and foothill areas (inland industrial estates of Chon Buri and Rayong) — usually sandy clay and lateritic soil from weathered rock (residual soil); some locations have shallow weathered rock, so piles can be shorter than in Bangkok or spread footings may be used. This must be confirmed by soil investigation because the depth to the hard layer changes quickly.
  • Lowlands and former paddy fields (parts of Chachoengsao, Prachin Buri and the border with Samut Prakan) — pockets of soft soil occur, so boreholes must be spread to cover heavily loaded zones.
Eastern Thailand soil layers in Chon Buri and Rayong change with terrain within a few kilometers Conceptual cross-section of three zones in the Chon Buri–Rayong area. Left is the coastal plain: below the surface are coastal sand and marine sediments, the groundwater table is close to the surface and may be saline, and boreholes are prone to collapse, so steel casing or drilling fluid is needed. Center is the inland and foothill area: lateritic soil and residual soil from weathered rock overlie shallow weathered rock, so piles are shorter than in Bangkok or spread footings may be possible. Right is the lowland or former paddy field: pockets of soft clay occur, and piles in these pockets must be longer than in adjacent areas. The depth to the hard layer therefore changes quickly and must be confirmed by soil investigation on the actual plot. Chon Buri–Rayong soils vary with terrain Not to scale Coastal plain Inland / foothill Low paddy Sea sand Sea silt Laterite/WR Rock Soft pockets 1 Coastal plain High GWL, maybe saline; caving risk 2 Inland / foothill Shallow hard layer: short piles/footings 3 Low paddy Soft pockets: spread boreholes
Conceptual cross-section of 3 zones in the Eastern region — the coastal plain has coastal sand and marine sediments with high groundwater; inland and foothill areas have lateritic soil and shallow weathered rock; lowlands and former paddy fields have pockets of soft soil. Pile lengths can therefore differ greatly within a few kilometers (conceptual illustration, not design data)

Because of this variability, using soil data from a neighboring plot to design a factory or warehouse in the Eastern region is riskier than in Bangkok. Read guidance on setting the number and depth of boreholes in How many boreholes and how deep? and the land checklist before building a factory

What has SPN done in Chon Buri–Rayong?

Examples of SPN projects in the EEC range from soil investigation to post-construction testing and inspection:

SPN team drilling with a tripod rig at a factory extension construction site in Rayong
Soil boring for a factory extension, Rayong — large factory sites require boreholes spread to cover heavy machinery and storage tank zones

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Table 1: Examples of SPN projects in the Chon Buri–Rayong (EEC) area
AreaProject typeWork performed
Rayong — petrochemical industrial estatePetrochemical plantSoil boring inside the estate under the plant's work permit and safety system
Rayong — industrial plantNew factory and extensionSoil boring + SPT with lab testing for design of machine foundations and production buildings
Rayong — factory projectPrestressed concrete driven pilesHigh-strain Dynamic Load Test (PDA) to verify pile load capacity (ASTM D4945 · DPT 1252-51)
Rayong — industrial estateSlab on grade / concrete yardPlate Bearing Test using the site excavator as reaction load (ASTM D1195/D1196 · DPT 1253-62)
Chon Buri — infrastructure projectDeep open excavation areaSoil boring for design of the earth retaining system and foundations
Chon Buri — LPG oil terminal / fuel depotPort and fuel storage tanksSoil boring for tank foundations and port structures
Chon Buri — building projectCompleted concrete structureChemical anchor Pull-Out Test (ASTM E488) and Concrete Core Test (ASTM C42), Si Racha District
Drop hammer striking the pile head during a high-strain Dynamic Load Test, factory project in Rayong
Dynamic Load Test (PDA) on piles for a factory project, Rayong — several piles can be tested per day, suitable for factories with many piles that need results before structural work starts
Pull-Out Test rig installed on a chemical anchor in a concrete structure, project in Chon Buri
Chemical anchor Pull-Out Test per ASTM E488, project in Chon Buri — a post-construction check often used at EEC factories when installing additional machinery or steel frames

What do you need to prepare before working in an industrial estate?

Work in industrial estates and petrochemical plants involves more safety procedures than typical sites, which affects the schedule. SPN is familiar with these requirements from regular work in the area. Project owners should prepare the following in advance:

  1. Site access documents — team list, ID card copies, and vehicle and machinery registrations, sent to the plant's or estate's safety department in advance as each site requires
  2. Safety training and Work Permit — most petrochemical plants require every team member to complete training and hold a daily work permit; allow 1 day before drilling starts
  3. Underground utility plans — locations of pipes, cables and underground chemical lines, to set safe borehole locations. If no drawings are available, SPN can scan with GPR before drilling
  4. Personal protective equipment per plant requirements — the SPN team already uses full PPE as standard, but some plants require additional equipment such as gas detectors, which must be known in advance
3D model of soil boring inside a petrochemical industrial estate and what to prepare before site entry 3D view of an area inside a petrochemical industrial estate near the coast, cut away to show the soil layers on the front and right faces: coastal sand, marine sediment, stiff clay and dense sand, with a shallow groundwater table. On the left is a security post with an entry barrier, where team documents and vehicle registrations must be submitted in advance. In the center a tripod rig is drilling a borehole, with a daily work permit sign and team members in full personal protective equipment holding a gas detector. In the background are liquid storage tanks and pipe racks on steel frames. Below the surface are several underground pipelines whose positions must be checked using plans or GPR before setting the borehole location. Depth not to scale. 3D model — soil boring in a petrochemical estate Not to scale Site access docs Team list, vehicle & rig reg. 1 Training + work permit Daily Work Permit 2 Full PPE + gas detector Per plant rules 4 Buried pipes in estate Use plans or GPR scan first 3 Depth compressed · Conceptual illustration
3D model — soil boring in a petrochemical estate ① submit site access documents at the security post in advance ② complete training and hold a daily work permit ③ check underground pipe locations from plans or GPR before drilling ④ team wears full PPE and uses a gas detector as the plant requires (depth not to scale)

How are prices and travel costs to Chon Buri–Rayong calculated?

SPN's main service prices use the same rates nationwide, plus travel and equipment mobilization costs based on the distance to the site:

  • Soil investigation — 2–3 storey houses start from about THB 20,000–40,000 (2–3 boreholes, including basic lab testing and an engineer-certified report); factory prices depend on the number and depth of boreholes. See Soil boring prices 2026
  • Pile testing — Seismic Integrity Test about THB 100–150/pile · Dynamic Load Test (PDA) from about THB 5,500/pile · Static Load Test THB 50,000–150,000+/pile. See Pile testing prices 2026
  • Eastern region travel costs — Rayong, Chon Buri and Chanthaburi are charged extra based on site distance and number of overnight stays, stated clearly in the quotation

The prices above are approximate starting prices and do not include travel and equipment mobilization costs, which are charged based on the distance to the site. Send the location and scope of work to get a free quote within 24 hours.

Summary

Chon Buri–Rayong is an area where SPN has an ongoing track record: soil boring in petrochemical estates and factory extensions, PDA pile testing, Plate Bearing Tests for factory floors, and post-construction structural inspection. Eastern soils are much more variable than Bangkok's, so soil investigation on the actual plot is a step that cannot be skipped. The SPN team travels from Samut Prakan and reaches the site within a day, is familiar with estate work permit systems, and delivers reports certified by a licensed engineer (COE license) for building permit applications and submission to relevant authorities. See all service areas on the soil investigation service page

📌 Note

The soil conditions in this article are a general overview of the area based on field experience, not design data for any particular plot. Actual foundation design must be based on the project's own soil investigation results and is the responsibility of the licensed design engineer.