METHODOLOGY OF TOPOGRAPHIC SURVEY  

AND GEOTECHNICAL INVESTIGATION 

FOR HON NUA ISLAND RESORT AREA PROJECT

A. TOPOGRAPHIC SURVEY 

I. INTRODUCTION 

In order to obtain the data for Hon Nua island area master plan, the topographic survey is required.

Figure 1. Project Location 

II. SURVEY QUANTITY. 

The survey quantity is described as follows: 

2.1. Establishment of Horizontal and Vertical control network: 

- IV order horizontal control network: 04 points. 

- Connecting to III order National control network: 02 points. 

- Grade 2 traverse control points: 10 points. 

- IV order vertical control network: 10 km. 

- Technical vertical control network: 05 km. 

2.2. Topographic survey:  

- Topographic survey for area 1 scale of 1:500, area: 15.0 ha, contour line at 1.0m interval. 

- Topographic survey for area 2 scale of 1:1000, area: 15.0 ha, contour line at 1.0m interval or 2.0m interval. 

The detailed survey quantity is shown in attached Figure 2: Survey area (Quatity final payment determined by actual survey results).

III. BASIS FOR SURVEY 

- National technical regulation on establishment of Horizontal control network QCVN 04:2009/BTNMT issued by Ministry of Natural Research and Environment in 2009. 

- National technical regulation on eshtablisment of leveling network QCVN 11: 2008/BTNMT issued by Ministry of Natural Research and Environment in 2008. 

- Technical standard of topographic survey at scale of 1/500, 1/1000, 1/2000, 1/5000 (96TCN43-90) issued by Vietnam National Land Administration Department (VNLAD).  

- Technical standard of GPS measurement for surveying in construction (TCXDVN 364 : 2006) issued by Ministry of Construction. 

- TCXDVN 309:2004 - Surveying in construction - General Requirements. 

- According to the technical requirements of the Client. 

IV. SURVEY METHODOLOGIES. 

IV.1 Reference datum. 

• Coordinate system:  

VN2000 coordinate system with central Meridian 108030', zone 30 (Ko=0.9999) shall be used for whole project. The detailed parameters of coordinate system are as follows: 

Spheroid 

Semi major axis 

1/ flattening 

Projection 

Central Meridian 

False Easting 

False Northing 

Scale factor at C.M : WGS 84 

: 6378137m 

: 298.257223563 

: UTM 

: 1080 30' E 

: 500 km 

: 0.000 

: 0.9999 

• Elevation system:  

- National Land Survey Datum shall be used for all maps. 

IV.2 Horizontal and vertical control network. 

IV.2.1 Establishing IV order and Grade 2 traverse horizontal network. 

Horizontal control points:  

Third order horizontal control points in VN2000 coordinate system established by Vietnam National Land Administration Department shall be used for developing the IV order network and Grade 2 traverse points. 

Point's location and monument dimension 

The IV order and grade 2 traverse networks will be designed inside survey area. Location of control points must satisfy the following requirements: 

- Locate at stable place and Convenient for GPS measurement. 

- Easy to use for survey work and the next steps. 

Control points shall be made of concrete with porcelain marker. Dimensions of IV order control points and grade 2 traveser points are 40×45×50cm and 20×25×30cm respectively. 

Full information of points such as name, date of construction, project name shall be written on the top. 

Field survey 

Horizontal control network must be connected to at least 02 National control points (III order or higher). 

All survey information of each measured point such as weather condition, Antenna's height, number of satellite must be recorded into daily report... All data collected at each point shall be recorded into memory card or internal memory with 10 seconds interval separately by names for post-processing.  

Post-processing and network adjustment 

Trimble business centre software shall be used for baselines processing and network adjustment.  

The final results shall include the errors of network according to Vietnamese standard such as point's position error, relative distance error, azimuth error... 

Coordinate in VN2000 grid coordinate system and WGS 84 Geographic coordinate system of control points shall be shown in the table. 

IV.2.2 Establishing IV order vertical control network. 

Vertical control points:  

Third or higher order National Benchmarks established by Vietnam National Land Administration Department shall be used for development of IV order vertical control network. 

Field survey 

In accordance with standard of V.N.L.A.D the IV order vertical control network will be established by using closed geometry levelling method. 

The benchmark location shall be chosen same as location of 02 National horizontal control points and 01 new point (point A) as basic for measurement technical level by GPS static.  

The IV order levelling route will run though 02 National horizontal control points and point A based on National benchmarks with miscloser of mm(where L is the length of levelling route in kilometre).  

Network adjustment 

The AENET or ANGEOMEX-93 software provided by Geodetic Department of Mining and Geology University shall be used for adjustment of IV order vertical control network. 

IV.2.3 Establishing technical vertical control network. 

Vertical control points:  

02 National horizontal control points and point A shall be used for development of technical vertical control network. 

Field survey 

Because survey area is the island, 2.0km from onshore, can not established by using closed geometry levelling method. So that technical vertical control network will be established by using GPS static method. 

The benchmark location shall be chosen same as location of IV order horizontal control points and grade 2 traverse points .  

We shall be use results of IV order horizontal control points and grade 2 traverse points for adjustment, We shall be measured add one section (include: 02 National points, 01 point A and 01 GPS) only.  

Network adjustment 

Results of GPS static measurement shall be combined for adjustment together Horizontal control network. 

IV.3 Topographic survey. 

Topographic survey work for areas shall be carried out as follow: 

? Field survey 

- The objects of topographic map including all existing surface features and other natural objects in accordance with map with scale of 1/500 and 1/1000 shall be measured by using Total stations.  

- Accuracy of the position and elevation of the detail points follow Technical standard 96TCN43-90. 

- Data survey shall be carried out 10mx10m interval for map with scale 1/500 and 20mx20m interval for map with scale 1/1000.  

- The measured data shall recorded into internal memory and then download to PC for post - processing and map editing. 

? Map editing 

- Topo software is then used to convert the XYZ values into a suitable format for final chart presentation by AUTOCAD 2007, File *.DWG. 

- Charts of each of the stipulated 1:500 and 1:1000 survey areas are to be produced on one or more A1 sheets. These charts are to depict: 

? Elevation relative to National Datum to the nearest 0.01m, contour lines on every 1.0m for scale 1:500 and 1.0m or 2.0m for scale 1:2000.  

? National Grid intersections as crosses at a spacing of 10cm on all sheets and annotated outside the net chart area; 

? In its various title and legend boxes all information necessary for a full understanding of the chart e.g. spheroid and grid data, elevation units, the coordinates of the UTM, scale bar, etc. 

V. SAFETY MEASURES 

During topographic survey the following safety measures must be applied: 

- During topographic survey the surveyors must wear safety helmet, safety shoes and keep off the fire/explode sources. 

VI. REPORTING. 

Drawings, reports must be made in 2 languages (English, Vietnamese). 

The topographic survey report consists of the following: 

• Technical report . 

• Appendix. 

- Original data and equipment's verification. 

- Results of horizontal and vertical control network. 

- Topographic maps with scale of 1:500 for area 1. 

- Topographic maps with scale of 1:1000 for area 2. 

- A CD diskette holding all present data in final report and surveyed data. 

VII. Time schedule and manpower 

VIII.1. Time schedule: 

- The detailed schedule is shown in the attached table. 

o Mobilize personnel, equipment: 03 days. 

o Complete all field survey work are: 20 days. 

(of which: Area 1 shall be finished in the day of 15th , Area 2 shall be finished in the day of 20th). 

o Demobilize personnel, equipment: 03 days 

o Make report at the office are: 14 days.

VIII.2. Manpower: 

- Manpower attended in the topographic survey is as the table below. 

No Job/Degree Responsibility Number Remarks 

1 Engineering in Geodesy . Technical Management 01 Officer in charge, general management 

2 Geodetic Eng. Field survey/Data processing and reporting 04  

3 Surveyor Field survey 04

Detailed organization chart are shown in attached figure.

List of Equipments and software shall be used 

The following equipments and software shall be used for survey work: 

No Equipment/software Name Made in/by Unit Quantity Purpose 

1 Single frequency Trimble R3 receivers or equivalent equipment USA set 04 Establishing control points 

2 Total station Topcon GTS 230N or equivalent equipment Japan set 01 Topographic survey 

3 Leveling instrument Topcon AT-B4 and stafts or equivalent equipment Japan set 01 Leveling 

4 Trimble business centre softwave - - - GPS network adjustment 

5 AENET softwave - - - Leveling network adjustment 

6 Topo software - - - Map editor 

7 Assistant office software - - - Reporting 

Organization Chart 

. GEOTECHNICAL INVESTIGATION 

I. INTRODUCTION 

This Technical Statement for Geotechnical Investigation describes the scope, detailed method and planned programmer for execution of the geotechnical investigation to be carried out at the Hon Nua island.  

The purpose of the Investigation is to provide geotechnical information of the sufficient input data for Hon Nua island area master plan project.  

II. SCOPE OF WORK AND ESTIMATED QUANTITY 

The full scope and estimated quantity of the geotechnical investigation is summarized, as in tables 1 below: 

Table 1 - Estimated quantities for site work 

No. Borehole Co-ordinate Depth (m) Soil type Sample SPT Remark 

Y (m) X (m) I-III (m) IV-VI (m) VII-VIII (m) UD D R I-III IV-VI  

1 BH1 - - 10 4 3 3 2 2 1 2 2 On Land 

2 BH2 - - 10 4 3 3 2 2 1 2 2 On Land 

Total 20 8 6 6 4 4 2 4 4  

Note:  

- U: Undisturbed samples; D: Disturbed samples; R: Rock core samples 

- Location of boreholes shall be choose by Client at site 

Table 2 - Estimated quantities of laboratory test  

No. Description Soil type Estimated 

No. of tests Standard (ASTM) 

1 Classification Tests 

- Natural moisture content 

- Unit weight 

- Specific gravity 

- Sieve and Hydrometer analysis 

- Aterberg limits 

- Permeability/ Dis-permeability 

- Organic matter All 8 D422/D4318/D2487/etc. 

2 Unconsolidated 

Un-drained Tri-axial Cohesive soil 4 D2850 

3 Consolidated 

Un-drained Tri-axial Cohesive soil 4 D4767 

4 Direct Shear Non-cohesive 

Granular  

5 Consolidation Cohesive soil 4 D2435 

6 Un-axial compression strength test Rock 2 D2938 

7 Point load strength test Rock 2 D5731

Geotechnical Investigation shall be carried out in accordance with following codes and standards, as in tables 2 below: 

Table 3 - Applicable Codes and Standards 

British Standards (BS) Relevant British Standards, in particular: 

? BS 1377-1990: Methods of test for soils for civil engineering purposes - Parts 1 to 9; 

? BS 5930-1999: Code of practice for site investigations. 

Standard Relevant ASTM - standard, in particular: 

? Volume 4-08 'Soil and Rock (I): D420 - D5779'; 

? Volume 4-09 'Soil and Rock (II): D5780 - latest'; Geo-synthetics'. 

Other codes or standards 22 TCN 259 - 2000: Codes of practice for exploration drilling published by Ministry of Transport of Vietnam 

III. EQUIPMENT AND INVESTIGATION METHODS 

III.1. General requisitions 

All work to be done for the soil investigation shall be performed in a sequence approved by the Consultant Employer. The locations of the field investigations will be in accordance with the information handed over by the Employer to the Contractor. 

The Contractor shall confirm with the Employer sufficiently in advance on the exact locations of the field investigations, together with instructions on what type of investigation(s) (boring, sampling and in-situ testing) shall be performed. 

The Contractor shall maintain in good working order, at all times during the period of execution of the field investigations, the instruments provided by him for the leveling, proper setting out of the boreholes, boring, sampling and in-situ testing. Said instruments shall be positioned on the Contractor's site sufficiently close to the actual location of the boreholes. 

The Contractor shall provide a high standard of management and technical supervision of the execution of the program. The field investigations shall carried out under the supervision of qualified and experienced sufficiently English speaking senior geotechnical engineers or similar. They shall be capable of competently logging the strata encountered both for any correlation between boreholes and the immediately production of an engineer's log. They shall be fully conversant with the theory and techniques of the in-situ test covered by the Specification. 

In case the Contractor, during the execution of a borehole, encounters an obstruction (such as, but not limited to ammunition, a wreck or boulders), which makes the continuation of the borehole impossible, the Contractor shall immediately carry out a new borehole at a new location within 2m from the original location. 

The Contractor shall keep all logbooks, records and samples in safe custody and shall not allow any person not dully authorized by the Employer to have access thereto. 

The number of Geotechnical Engineers or similar, which shall be part of the Contractor's Team carrying out the field investigations, shall equal the number of shifts.  

III.2. Positioning and determining elevation 

Co-ordinates shall be in UTM WGS 84, Central Meridian 1080 30'E, zone 30. Scale factor at Central Meridian 0.9999. 

Elevations shall be in National Datum. 

The location of the boreholes shall be determined by using DGPS instruments or hand held GPS, according to polar co-ordinate method or any other methods approved by the Employer. 

The actual location of the borehole shall be within 2.0m from the desired location. 

Elevation of the offshore boreholes shall determine by using direction method from local benchmark.  

The actual Elevation of the borehole shall be within 0.1m. 

III.3. Boring 

III.3.1 Boring equipment: 

01 drilling machines XY-1A of Chinese manufacturer with maximum capacity of 150m shall be used to carry out the boring with jack-up pontoon. 

Drilling methods shall be rotary, core rotary or percussion drilling with betonies solution. 

Before boring commences the Contractor shall obtain the approval of the Employer to the types of equipment and methods he proposes to use. After commencing a borehole the Contractor shall not change his method of boring without the approval of the Engineer. 

The minimum starting diameter of the borehole shall be sufficient to allow the proposed borings to be completed with a minimum diameter of 127 mm. 

During boring, the operator shall raise the tools from the borehole slowly in order to minimize effects of suction or disturbance. 

No casing shall be withdrawn until the Employer has given his consent for the termination of the borehole. 

All depths of samples, test and changes of strata shall be measured with an accuracy of 0.1m. 

III.3.2. Boring depth: 

Proposed depths of each boring are indicated in table 1. 

However, all boring depth shall be controlled by the actual soil conditions or obstacles encountered.  

All boreholes shall be extended through unsuitable foundation strata to reach hard or compact materials of suitable bearing capacity. 

In the project area, all boreholes shall be extended into compact gravely/sandy/clayey layer which has N-values greater than 35 blows/75mm shall be requested to reach as the layer of bearing capacity or into bed rock at least 3m. 

During boring following information shall be recorded and then submitted to the Employer: 

• Borehole number and times of commencement and completion of boring; 

• Site, co-ordinates and reduced ground surface elevation; 

• Boring technique, and type of plant; 

• Boring diameter and progress; 

• Casing diameter and progress; 

• Depth and thickness of each stratum; 

• Geotechnical description - color, in-situ compactness/strength and structure, weathered state, minor lithological characteristics and additional descriptive terms including presence of mica, soil and rock name (in capitals), organic matter, other terms indicating the special engineering characteristics, all in accordance with ASTM D2488; 

• Ancillary geotechnical information; 

• Sample depth and types; 

• Depth and result of in-situ standard penetration (SPT); 

• Symbolic log; 

• Any further relevant information either required by the Engineer or observed by the Contractor. 

III.4. Sampling 

For sampling, thin-walled tube samplers with minimum 300mm in length or Piston/double tube samples with 1000mm in length and 110mm in inside diameter shall be used. In general, all sampling equipment shall be to the approval of the Employer. 

Before sampling in a borehole, the bottom of the boring shall be carefully cleaned from loose materials and where a casing is being used, the sample shall be taken below the bottom of the casing. 

• Unless otherwise instructed by the Employer, undisturbed samples shall be taken in cohesive soils every 2.0m interval of depth in clayey layer by either thin wall tube/ piston sampler (N<8) and/ or as designated by the Employer. 

• Where an attempt to take an undisturbed sample is not successful, the boring shall be cleaned out for the full depth to which the sampling tube has been driven and a new attempt shall be made. 

• Disturbed and SPT samples (the samples taken from split-barrel sampler when carrying out SPT tests) shall be taken in non-cohesive soils or/and where undisturbed sample cannot be taken.  

• Rock sample: Rotary drilling shall be carried out using a wire line Geobore 'S' system or similar with double tube with core liner coring system incorporating a removable liner. Rotary core drilling shall produce cores of not less than 95% in any drill run in not normally be acceptable unless the Client is satisfied that more than 95% recovery is impracticable under the prevailing conditions. Continue coring is required in accordance with BS 5930 or equivalent for in-situ sampling, identification and testing for entire boring length. The rock sample shall allow the assessment of total core recovery (TCR), solid core recovery (SCR), and fracture index and rock quality designation (RQD). 

All cores, rock and soil, shall be describe and classified according the relevant sections of BS 5930:1999. 

No undisturbed samples shall remain in the open for more than one hour. All samples shall be protected at all times from direct sunlight. 

Labeling of the samples shall be with indelible ink and the labels shall be durable such that deterioration with time does not occur. All samples shall be labeled immediately after being taken. Each label shall include the following information: 

• Borehole number and site and location references; 

• Date of the sample; 

• Depth of the top and bottom of the sample; 

• Soil and rock description; 

• Type of the sample.  

The Contractor shall be responsible for a proper preparation, storage and transportation of samples. As soon as reasonably possible the Contractor shall transport all samples from the sample store to the laboratory. 

III.5. Standard Penetration Test (SPT) 

SPT shall be carried out according to ASTM D1586. 

In all boreholes, SPT tests shall be performed at every 1.5m depth interval. Before testing, the bottom of the borehole also shall be cleaned from loose materials and assures that the tests shall not be performed on disturbed soil. Record the number of blows each 15cm of penetration as N1, N2, and N3 correlative. 

III.6 Laboratory testing 

All tests and reporting of result, including description of samples shall be in accordance with appropriate designation of the ASTM standard, as follows: 

No. Property/Test Standard 

1 Specific Gravity ASTM D 854 

2 Water Content ASTM D 2216 

3 Grains size analysis (Sieve and Hydrometer Test) ASTM D 422 

4 Unit Weight ASTM D7263 

5 Consistency, Liquid limit, plastic limit, shrinkage limit ASTM D 4318 

6 Unconfined compression test on cohesive soil ASTM D2166  

7 Unconfined compression test of intact rock core specimens ASTM D2938 

8 UU tri-axial test ASTM D2850 

9 CU tri-axial test ASTM D4767 

10 Consolidation Test ASTM D2435 

11 Direct Shear ASTM D3080 

12 Point load strength test ASTM D5731 

13 Organic matter ASTM D2974-07a 

The samples to be tested, the properties to be determined and program of testing shall be instructed by the Employer. The program of testing shall not be changed without the approval of the Employer.  

One copy of the all laboratory data sheets shall be included as an appendix to the final report. 

III.7. Hydrologic geology investigation 

It shall be carried out hydrologic geology investigation for 30ha of project area, 03 locations shall be investigated for seeking and estimated the fresh water for the project.  

III.8. Photograph 

All boreholes shall be taken photograph. Each photograph shall display the project name, borehole/test pit number, site and dates (commencing and completing).  

After completing a borehole, all its samples shall be put on wooden boxes in order of depth and taken photograph.  

Each photograph shall clearly show all necessary details and shall contain a graduated scale, which shall be the same in every photograph. Ensure that the following criteria are fulfilled for each photograph: 

• A graduated scale in centimeters, labels and other remarks; 

• A clearly legible reference board identifying the project title, borehole number, date and depth of drill runs; 

• The length of the sample box in each photograph fills the frame; 

• The focal plane of the camera and the plane of the sample box are parallel; 

The camera is placed in the same position with respect to the sample box in every photograph. 

III.9. Reporting 

III.9.1 Daily Report 

Daily report shall be submitted to the Employer at the end of working time of the next day on site. The content of this report shall include: 

• Contract's title and site location; 

• Contractor's and Operator's name; 

• Borehole number and its co-ordinates; 

• Weather condition, time, date; 

• Brief description of equipment and techniques in use, summary of work carried out and weather conditions; 

• Diameter and depth of borehole and casing; 

• Depth of each stratum; 

• Description for each stratum; 

• Type of samples, the depths from which they have been taken, the methods used. 

• The depths and details of all in-situ tests; 

• Type of drilling fluid; 

• Type of core barrel and bit used; 

• Depth of start and finish of each core run; 

• Core's diameter and depths of changes in core diameter; 

• Color and condition of the return drilling fluid; 

• Depth of loss of return drilling fluid (if happened); 

• Total core recovery and percentage recovery with information as to possible location of core losses, if any, for each core run; 

• Any further relevant information observed by the Contractor. 

III.9.2 Preliminary report 

The Employer may request to see copies of the preliminary geological boring log of a specific borehole not less than 2 (two) days after completion of boring. 

III.9.3 Final Report 

A draft of the Final report shall be submitted to the Employer not less than 01 (one) week after completion of laboratory testing. And within 01 (one) week after receipt of comments/recommendations/instructions of the Employer on the draft, the Final report shall be submitted to him. 

The final report shall be written in English and Vietnamese. Copies of the final report shall be provided to the Engineer. 

The Final report shall contain (but not limited) the following information and data: 

• Introduction: 

? Bases of the investigation; 

? Brief description of the purpose of the investigation; 

? Name of the study; 

? Location of the work site; 

? Period of the works; 

? Brief description of the tests performed; 

? Quantity of geotechnical investigation; 

• Description of general conditions of the borehole site: 

? Geological history and conditions of the site; 

? Topography of the site; 

• Engineering geological characteristics of the project area; 

• Table of Location and co-ordinates of boreholes; 

• Borehole logs: 

• Cross sections and profiles; 

• Result of FVST tests; 

• Some geotechnical recommendations; 

• Laboratory testing results (appendix).

IV. PLANNED PROGRAMMER 

IV.1. Equipment 

Following equipment shall be used for site investigation: 

No. Equip. Name Model/Manufacturer Capacity Unit Quantity 

1 Rotary coring type XY-1A, XJ100/China 150m No. 01 

2 Hydraulic pump China - No. 01 

3 Positioning Total Station/England 

DGPS/France - No. 01 

01 

4 Leveling Pentax/Japan - No. 01 

5 SPT Vietnam - No. 01 

6 Thin walled tube sampler Vietnam - Set 01 

7 Piston sample Japan - Set 01 

8 Double tube Vietnam - Set 01 

9 Drilling rod China - Meter 50 

10 Casing China - Meter 20 

11 Boat for worker transportation - - No. 01 

12 Transceiver ICOM/Japan 10 km No. 03 

13 Other accessories - - - - 

IV.2. Manpower 

Manpower shall take part in the geotechnical investigation, as in the table below. 

No. Job & Degree Responsibility Number Remarks 

1 Qualified geotechnical engineer Manager & officer in charge 01 QC 

2 Geotechnical engineer Field manager and recording 02 - 

3 Worker Drilling 04 - 

4 Operator Operate drilling 01 - 

5 Surveyor Positioning and leveling 02 - 

6 Lab staff Lab testing 05 - 

7 Geotechnical engineer Making report 02 - 

IV.3. Time and schedule 

Draft timetable is as following table.