REDUCING RISK AND VISITOR IMPACTS

Transcription

1 REDUCING RISK AND VISITOR IMPACTS Trenchless Solutions for Liberty Island Paul J. Mourt, PE

2 Project Rules To Live By 1 Expect the Unexpected Do your homework 2 Risks need to be evaluated on every project 3 There s more than one way to complete a project 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 2

3 PRESENTATION OUTLINE 1 Project Overview and Background 2 HDD Risk Issues 3 Construction Results

4 PROJECT OVERVIEW AND BACKGROUND

5 Project Purpose and Overall Objective Replace undersized water and sewer pipelines serving Liberty Island Reduce vulnerability of pipelines to damage Minimize impacts to visitors of Liberty Island and Liberty State Park Preserve the Visitor Experience was an oft-repeated phrase 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 5

6 Stakeholders National Park Service Liberty State Park / State of New Jersey Jersey City MUA Carson Corporation Mott MacDonald Perceived risk varied among stakeholders 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 6

7 Vulnerability of Existing Utilities 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 7

8 Trenchless Techniques Horizontal Directional Drilling Pipebursting 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 8

9 Project Components 12 Water 2,400 LF installed by HDD 6 Sewer 2,400 LF installed by HDD 10 Water 3,000 LF installed by Pipebursting 4 Sewer 3,000 LF installed by Sliplining 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 9

10 Project Components 12 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 10

11 Background Liberty Island 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 11

12 Background Liberty State Park 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 12

13 Geotechnical Investigation 8 borings land and subaqueous Sampling of overburden Rock corings RQD 50% to 80% UCS 3,480 psi to 25,070 psi 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 13

14 Desired Strata bedrock layer +/- 15 feet into bedrock +/- 80 feet deep on land +/- 60 feet deep under harbor Bending radii +/ feet Entry / exit angles 12 to 13 degrees 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 14

15 HDD RISK ISSUES 1 Horizontal Curvature 2 Hydraulic Fracture 3 Maintaining Water Service (Rig Placement)

16 HDD Risk Issue 1 Horizontal Curvature 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 16

17 HDD Risk Issue 1 (cont d) Superstorm Sandy helped 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 17

18 HDD Risk Issue 1 Horizontal Curvature 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 18

19 HDD Risk Issue 2 Hydraulic Fracture Evaluation In general accordance with Delft Geotechnics Method Developed for soil installations No accepted method to model/estimate maximum allowable drilling pressure in bedrock materials Elected to model the bedrock mass as a solid with properties similar to that of the overburden (conservative) 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 19

20 HDD Risk Issue 2 Hydraulic Fracture Evaluation Single Rig 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 20

21 HDD Risk Issue 2 Hydraulic Fracture Evaluation Dual Rig 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 21

22 Selected Method - Risk Issue 2 Drill and Intersect Method Conductor casings at each end 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 22

23 HDD Risk Issue 3 Maintaining Water Service ISSUE: Limited space on Liberty Island DESIGN: Install temporary water tanks and pumps CONSTRUCTION: Tighten entry angle and bending radius; leave existing system in place 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 23

24 CONSTRUCTION RESULTS 1 Hydraulic Fractures 2 Pipebursting 3 Monday Morning Quarterback

25 Construction Results Hydraulic Fractures Some difficulty installing conductor casings in Liberty State Park through fill Water line completed without incident Contractor did change to drilling 90% from Liberty State Park 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 25

26 Construction Results Hydraulic Fractures Sewer line drilled 30 feet horizontally from water line Frac out occurred when drill was 1,400 feet out 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 26

27 Construction Results Pipebursting Anticipated: 300 feet per hour Actual: 100 to 160 feet per hour Assumed 4 feet of cover Actual: up to 9 feet of cover Encountered MJ bells and repair clamps Fitting(s) required change to HDD 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 27

28 Monday Morning Quarterback Rig Placement on Liberty Island Conservative geometric layout of entry angles and radii allowed contractor to make adjustments Conductor No issues on Liberty Island not going to bedrock Would have helped to have initially installed conductor casing to bedrock in LSP 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 28

29 Monday Morning Quarterback Pipebursting Issues Alignment Accuracy Pipe Depth Bell Orientation 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 29

30 Conclusions Original Rules Expect the unexpected Do your homework Risks need to be evaluated on every project Rule Commentary Risk reduction does not mean that there won t be problems Perception of risk varies among stakeholders There s more than one way to complete a project Flexibility (and determination) can be key to project success 21/09/2017 Mott MacDonald Reducing Risk and Visitor Impacts: Trenchless Solutions for Liberty Island 30

31 Thank you Jersey City MUA National Park Service Carson Corporation